Merge pull request 'feat(watcher): inbox zero — archived raw/ originals are removed, not copied' (#206) from wt/inbox-zero into main

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>

.context/PROJECT.md

@@ -84,3 +84,15 @@ When acting as a coding agent on this project:
 4. Never modify files outside the project root without explicit permission
 5. When adding a dependency, explain why in the commit message
 6. For client projects: never send code or context to cloud APIs — use local models via LiteLLM
+
+## `main` is protected: ship by PR (local-dev#42, decided 2026-10-08)
+
+Gitea refuses direct pushes to `main` in this repo, and a PR merges only after its CI status (`CI / Lint / Test / Vet (pull_request)`) passes.
+**Why:** local-dev rule 5's reviewed lane (risk/medium+ is reviewed by a human) was enforced on the merge tools
+(`tbd_ship`, `pr_merge`: gitea-mcp v0.17.0/v0.18.0, merge only for an issue labelled exactly `risk/low` with green CI)
+but not on a direct commit to `main`, which bypassed it. This overrides rule 5's "risk/low commits straight to main"
+for this repo; control code is where the lane matters.
+**How:** `tbd_ship` for a one-file change, or branch -> PR -> `pr_merge` (name the `risk/low` issue); above `risk/low`
+open the PR and a human merges it in the Gitea UI after review. Tags are not protected. CD jobs push image tags to
+the **infra** repo with deploy keys, never to this repo's `main`. Undo (Mathias only): Settings -> Branches, or
+`PATCH /repos/mathias/hyperguild/branch_protections/main {"enable_push": true}`.

.context/system-prompt.txt

@@ -164,6 +164,63 @@ These rules apply to every task across every project, regardless of harness.
    the thing it was named for was exploitable. If you cannot name the mechanism,
    you do not yet know what the test observes.
 
+10. **Short sessions, one rc per repo, edit only in a locked worktree of the repo
+   you are changing** (ADR-0002, accepted 2026-10-06).
+   - One session per issue or task, ending with rule 6's close ritual. Related
+     issues may share a session only when they share a worktree and an owner.
+     State that must outlive the session goes in an issue, not the chat.
+   - Start `claude rc` in the repo you will edit (`infra`, `trucker-ecommerce`,
+     `hyperguild`, ...), not in `~/dev`: the rc worktree is a worktree of the
+     launch directory's repo, so launched from `~/dev` it protects nothing you
+     edit (measured: 73% of edits landed in shared checkouts). Start it only
+     while working there.
+   - Keep at most one thin `~/dev` coordinator session. It files issues and hands
+     out tasks; it reads and edits no sub-repo code.
+   - Split cross-repo work per repo. The contract between the halves lives in an
+     issue on each repo.
+   - Edit in a worktree of that repo, locked at creation:
+     `scripts/wt.sh add <repo> <task>` does it (fetch, `wt/<task>` from origin/main, lock);
+     `scripts/wt.sh done <repo>-<task>` removes it after the push and refuses dirty or
+     unpushed work. By hand: `git worktree add ~/worktrees/<name> -b <branch> origin/main`
+     then `git worktree lock --reason "manual: <purpose>" ~/worktrees/<name>`.
+   - Before working a repo another session may touch, announce your issue list to
+     that session (`SendMessage`) and ask for theirs.
+   - Auto-memory is keyed by cwd, so a repo rc starts without it. Cross-repo
+     working rules live in brain (`wiki/homelab/decisions/2026-10-06-062416-auto.md`, wing homelab, hall
+     decisions) and the section below, not in per-directory memory.
+
+## Standing footguns
+
+Each cost real time once. Detail and evidence: brain `wiki/homelab/decisions/2026-10-06-062416-auto.md` (title standing-working-rules).
+
+- **Gate then commit with `&&`, never `;`.** "Green" means exit code 0 and
+  `grep -c FAIL` is 0, not a filtered grep.
+- **Stage by path, never `git add -A` or `git add .`** (they stage from the repo
+  root and swept in other sessions' work twice). Check `git status --porcelain` first.
+- **Before committing in a shared checkout:** `git branch --show-current`.
+- **Before tagging:** `git fetch origin --tags`, then `git describe --tags --abbrev=0 <sha>`
+  and `git tag --sort=-v:refname | head`; go above both. Never take the last tag
+  from a report.
+- **Run only what the project's gate runs.** No repo-wide formatter unless the gate
+  runs it.
+- **Reproduce a CI red at the cited commit before applying an issue's prescribed fix.**
+- **Read an issue's comments (`issue_list_comments`), not just its body, before working it.**
+- **A comment naming a control ("behind branch protection") is not evidence; query
+  the control.** A working detector can hide a missing preventer.
+- **On koala the MCP servers are `mcp__plugin_skills_{brain,gitea,infra}__*`.** The
+  per-turn auth reminder is not evidence; call the tool or run `claude mcp list`.
+  Brain writes always pass `wing` + `hall`.
+- **`cat /etc/hostname` before assuming which host you are on.**
+- **Never run bare `git remote -v` or `git config --list`** (url.insteadOf expands
+  into a live token); use `git config --get remote.origin.url`.
+- **On koala `sudo` is denied outright; k8s exec, env dumps and flux reconcile need
+  per-action approval; decrypting a SOPS file and printing in one Bash call is
+  hook-blocked.** Do the repo-side work and hand the host-side step over in an issue.
+- **`set -o pipefail` plus an optional `grep | head | awk` dies on no match:** append `|| true`.
+- **Gitea `file_write_branch` takes plain text, not base64.**
+- **`OP_SERVICE_ACCOUNT_TOKEN` in the shell is read-only for `op`.** Operational
+  secrets go in the AgentSecrets vault via `set -a; . ~/.op-agent-write.env; set +a`.
+
 ## CAD sprint patterns
 
 Two CAD sprint archetypes (defs: brain `wiki/homelab/decisions/continuous-agentic-development-cad-concept-2026-06-16`):
@@ -244,25 +301,20 @@ Three machines on Tailscale:
 
 All development repos live at `~/dev/` (softlink from `~/Documents/local-dev/`).
 
-Organized in thematic folders:
+Organized by **role**, because the role decides which rules apply (ADR-0003):
 
-| Folder | Focus | Count |
-|--------|-------|-------|
-| `GO/` | Go web frameworks, API integrations, learning projects | ~10 |
-| `AI/` | ML research, AI frameworks (FinRL, DSPy, crawl4ai) | ~6 |
-| `AGENTS/` | Autonomous agents, coding agents, MCP servers, infra | ~15 |
-| `QKX/` | Invoice processing, financial automation, payment systems | ~13 |
-| `XT/` | Climate data, sustainability (Klimatkollen, Garbo) | ~2 |
+| Folder | Role | Rules that key off it |
+|--------|------|-----------------------|
+| `platform/` | infra, brain, hyperguild, gitea-mcp, dispatch, shared tooling | control code (rule 8), GitOps review lane |
+| `products/` | tapir, cobalt-dingo, openbanking-api, ... | ordinary trunk-based work |
+| `clients/` | client work | local models only, never cloud APIs (Client work rules) |
+| `spikes/` | throwaway | no ceremony |
 
-See `~/dev/PROJECT_SUMMARY.md` for detailed descriptions of each project.
-
-### Key active projects
-
-- **super-koala** (`AGENTS/`) — multi-component agent stack with LangGraph, DSPy, MCP
-- **azure-tiger** (`QKX/`) — invoice extraction → ISO 20022 payment instructions
-- **gocrwl** (`AGENTS/`) — Go web crawler with containerized deployment
-- **koala-ai-stack** (`AGENTS/`) — local AI server infrastructure management
-- **klimatkollen** (`XT/`) — Swedish municipal climate data platform
+New projects are born into a role folder (`task new-project -- <name> <client|personal>
+<role-folder>`); a client tag requires `clients/` and `clients/` requires a client tag.
+Existing repos still sit in the old `AGENTS/` and `AI/` folders until they are moved one by
+one (ADR-0003 step 3). `~/dev/PROJECT_SUMMARY.md` (generated) lists every repo and where it
+is. How a session runs on koala (worktrees, rc per repo, the reaper, memory): `docs/working-on-koala.md`.
 
 ## Knowledge base — actively use it
 
@@ -514,4 +566,16 @@ When acting as a coding agent on this project:
 5. When adding a dependency, explain why in the commit message
 6. For client projects: never send code or context to cloud APIs — use local models via LiteLLM
 
+## `main` is protected: ship by PR (local-dev#42, decided 2026-10-08)
+
+Gitea refuses direct pushes to `main` in this repo, and a PR merges only after its CI status (`CI / Lint / Test / Vet (pull_request)`) passes.
+**Why:** local-dev rule 5's reviewed lane (risk/medium+ is reviewed by a human) was enforced on the merge tools
+(`tbd_ship`, `pr_merge`: gitea-mcp v0.17.0/v0.18.0, merge only for an issue labelled exactly `risk/low` with green CI)
+but not on a direct commit to `main`, which bypassed it. This overrides rule 5's "risk/low commits straight to main"
+for this repo; control code is where the lane matters.
+**How:** `tbd_ship` for a one-file change, or branch -> PR -> `pr_merge` (name the `risk/low` issue); above `risk/low`
+open the PR and a human merges it in the Gitea UI after review. Tags are not protected. CD jobs push image tags to
+the **infra** repo with deploy keys, never to this repo's `main`. Undo (Mathias only): Settings -> Branches, or
+`PATCH /repos/mathias/hyperguild/branch_protections/main {"enable_push": true}`.
+
 ---

AGENTS.md

@@ -159,6 +159,63 @@ These rules apply to every task across every project, regardless of harness.
    the thing it was named for was exploitable. If you cannot name the mechanism,
    you do not yet know what the test observes.
 
+10. **Short sessions, one rc per repo, edit only in a locked worktree of the repo
+   you are changing** (ADR-0002, accepted 2026-10-06).
+   - One session per issue or task, ending with rule 6's close ritual. Related
+     issues may share a session only when they share a worktree and an owner.
+     State that must outlive the session goes in an issue, not the chat.
+   - Start `claude rc` in the repo you will edit (`infra`, `trucker-ecommerce`,
+     `hyperguild`, ...), not in `~/dev`: the rc worktree is a worktree of the
+     launch directory's repo, so launched from `~/dev` it protects nothing you
+     edit (measured: 73% of edits landed in shared checkouts). Start it only
+     while working there.
+   - Keep at most one thin `~/dev` coordinator session. It files issues and hands
+     out tasks; it reads and edits no sub-repo code.
+   - Split cross-repo work per repo. The contract between the halves lives in an
+     issue on each repo.
+   - Edit in a worktree of that repo, locked at creation:
+     `scripts/wt.sh add <repo> <task>` does it (fetch, `wt/<task>` from origin/main, lock);
+     `scripts/wt.sh done <repo>-<task>` removes it after the push and refuses dirty or
+     unpushed work. By hand: `git worktree add ~/worktrees/<name> -b <branch> origin/main`
+     then `git worktree lock --reason "manual: <purpose>" ~/worktrees/<name>`.
+   - Before working a repo another session may touch, announce your issue list to
+     that session (`SendMessage`) and ask for theirs.
+   - Auto-memory is keyed by cwd, so a repo rc starts without it. Cross-repo
+     working rules live in brain (`wiki/homelab/decisions/2026-10-06-062416-auto.md`, wing homelab, hall
+     decisions) and the section below, not in per-directory memory.
+
+## Standing footguns
+
+Each cost real time once. Detail and evidence: brain `wiki/homelab/decisions/2026-10-06-062416-auto.md` (title standing-working-rules).
+
+- **Gate then commit with `&&`, never `;`.** "Green" means exit code 0 and
+  `grep -c FAIL` is 0, not a filtered grep.
+- **Stage by path, never `git add -A` or `git add .`** (they stage from the repo
+  root and swept in other sessions' work twice). Check `git status --porcelain` first.
+- **Before committing in a shared checkout:** `git branch --show-current`.
+- **Before tagging:** `git fetch origin --tags`, then `git describe --tags --abbrev=0 <sha>`
+  and `git tag --sort=-v:refname | head`; go above both. Never take the last tag
+  from a report.
+- **Run only what the project's gate runs.** No repo-wide formatter unless the gate
+  runs it.
+- **Reproduce a CI red at the cited commit before applying an issue's prescribed fix.**
+- **Read an issue's comments (`issue_list_comments`), not just its body, before working it.**
+- **A comment naming a control ("behind branch protection") is not evidence; query
+  the control.** A working detector can hide a missing preventer.
+- **On koala the MCP servers are `mcp__plugin_skills_{brain,gitea,infra}__*`.** The
+  per-turn auth reminder is not evidence; call the tool or run `claude mcp list`.
+  Brain writes always pass `wing` + `hall`.
+- **`cat /etc/hostname` before assuming which host you are on.**
+- **Never run bare `git remote -v` or `git config --list`** (url.insteadOf expands
+  into a live token); use `git config --get remote.origin.url`.
+- **On koala `sudo` is denied outright; k8s exec, env dumps and flux reconcile need
+  per-action approval; decrypting a SOPS file and printing in one Bash call is
+  hook-blocked.** Do the repo-side work and hand the host-side step over in an issue.
+- **`set -o pipefail` plus an optional `grep | head | awk` dies on no match:** append `|| true`.
+- **Gitea `file_write_branch` takes plain text, not base64.**
+- **`OP_SERVICE_ACCOUNT_TOKEN` in the shell is read-only for `op`.** Operational
+  secrets go in the AgentSecrets vault via `set -a; . ~/.op-agent-write.env; set +a`.
+
 ## CAD sprint patterns
 
 Two CAD sprint archetypes (defs: brain `wiki/homelab/decisions/continuous-agentic-development-cad-concept-2026-06-16`):
@@ -239,25 +296,20 @@ Three machines on Tailscale:
 
 All development repos live at `~/dev/` (softlink from `~/Documents/local-dev/`).
 
-Organized in thematic folders:
+Organized by **role**, because the role decides which rules apply (ADR-0003):
 
-| Folder | Focus | Count |
-|--------|-------|-------|
-| `GO/` | Go web frameworks, API integrations, learning projects | ~10 |
-| `AI/` | ML research, AI frameworks (FinRL, DSPy, crawl4ai) | ~6 |
-| `AGENTS/` | Autonomous agents, coding agents, MCP servers, infra | ~15 |
-| `QKX/` | Invoice processing, financial automation, payment systems | ~13 |
-| `XT/` | Climate data, sustainability (Klimatkollen, Garbo) | ~2 |
+| Folder | Role | Rules that key off it |
+|--------|------|-----------------------|
+| `platform/` | infra, brain, hyperguild, gitea-mcp, dispatch, shared tooling | control code (rule 8), GitOps review lane |
+| `products/` | tapir, cobalt-dingo, openbanking-api, ... | ordinary trunk-based work |
+| `clients/` | client work | local models only, never cloud APIs (Client work rules) |
+| `spikes/` | throwaway | no ceremony |
 
-See `~/dev/PROJECT_SUMMARY.md` for detailed descriptions of each project.
-
-### Key active projects
-
-- **super-koala** (`AGENTS/`) — multi-component agent stack with LangGraph, DSPy, MCP
-- **azure-tiger** (`QKX/`) — invoice extraction → ISO 20022 payment instructions
-- **gocrwl** (`AGENTS/`) — Go web crawler with containerized deployment
-- **koala-ai-stack** (`AGENTS/`) — local AI server infrastructure management
-- **klimatkollen** (`XT/`) — Swedish municipal climate data platform
+New projects are born into a role folder (`task new-project -- <name> <client|personal>
+<role-folder>`); a client tag requires `clients/` and `clients/` requires a client tag.
+Existing repos still sit in the old `AGENTS/` and `AI/` folders until they are moved one by
+one (ADR-0003 step 3). `~/dev/PROJECT_SUMMARY.md` (generated) lists every repo and where it
+is. How a session runs on koala (worktrees, rc per repo, the reaper, memory): `docs/working-on-koala.md`.
 
 ## Knowledge base — actively use it
 
@@ -508,3 +560,15 @@ When acting as a coding agent on this project:
 4. Never modify files outside the project root without explicit permission
 5. When adding a dependency, explain why in the commit message
 6. For client projects: never send code or context to cloud APIs — use local models via LiteLLM
+
+## `main` is protected: ship by PR (local-dev#42, decided 2026-10-08)
+
+Gitea refuses direct pushes to `main` in this repo, and a PR merges only after its CI status (`CI / Lint / Test / Vet (pull_request)`) passes.
+**Why:** local-dev rule 5's reviewed lane (risk/medium+ is reviewed by a human) was enforced on the merge tools
+(`tbd_ship`, `pr_merge`: gitea-mcp v0.17.0/v0.18.0, merge only for an issue labelled exactly `risk/low` with green CI)
+but not on a direct commit to `main`, which bypassed it. This overrides rule 5's "risk/low commits straight to main"
+for this repo; control code is where the lane matters.
+**How:** `tbd_ship` for a one-file change, or branch -> PR -> `pr_merge` (name the `risk/low` issue); above `risk/low`
+open the PR and a human merges it in the Gitea UI after review. Tags are not protected. CD jobs push image tags to
+the **infra** repo with deploy keys, never to this repo's `main`. Undo (Mathias only): Settings -> Branches, or
+`PATCH /repos/mathias/hyperguild/branch_protections/main {"enable_push": true}`.

CLAUDE.md

@@ -84,3 +84,15 @@ When acting as a coding agent on this project:
 4. Never modify files outside the project root without explicit permission
 5. When adding a dependency, explain why in the commit message
 6. For client projects: never send code or context to cloud APIs — use local models via LiteLLM
+
+## `main` is protected: ship by PR (local-dev#42, decided 2026-10-08)
+
+Gitea refuses direct pushes to `main` in this repo, and a PR merges only after its CI status (`CI / Lint / Test / Vet (pull_request)`) passes.
+**Why:** local-dev rule 5's reviewed lane (risk/medium+ is reviewed by a human) was enforced on the merge tools
+(`tbd_ship`, `pr_merge`: gitea-mcp v0.17.0/v0.18.0, merge only for an issue labelled exactly `risk/low` with green CI)
+but not on a direct commit to `main`, which bypassed it. This overrides rule 5's "risk/low commits straight to main"
+for this repo; control code is where the lane matters.
+**How:** `tbd_ship` for a one-file change, or branch -> PR -> `pr_merge` (name the `risk/low` issue); above `risk/low`
+open the PR and a human merges it in the Gitea UI after review. Tags are not protected. CD jobs push image tags to
+the **infra** repo with deploy keys, never to this repo's `main`. Undo (Mathias only): Settings -> Branches, or
+`PATCH /repos/mathias/hyperguild/branch_protections/main {"enable_push": true}`.

ingestion/cmd/server/main.go

@@ -179,9 +179,12 @@ func alertingWarnings(getenv func(string) string) []string {
 	return out
 }
 
-func buildNotifier() audit.Notifier {
-	if n := audit.NewNtfyNotifier(os.Getenv("BRAIN_NTFY_URL"), os.Getenv("BRAIN_NTFY_TOKEN")); n != nil {
-		return n
+// buildNotifier returns the ntfy notifier for one alert source, titled so
+// the source is recognisable (hyperguild#163), or nil when ntfy is not
+// configured.
+func buildNotifier(getenv func(string) string, title string) audit.Notifier {
+	if n := audit.NewNtfyNotifier(getenv("BRAIN_NTFY_URL"), getenv("BRAIN_NTFY_TOKEN")); n != nil {
+		return n.WithTitle(title)
 	}
 	return nil
 }
@@ -203,7 +206,7 @@ func buildAuditSink(ctx context.Context, brainDir string, logger *slog.Logger) c
 		logger.Error("capture audit buffer init", "err", err)
 		os.Exit(1)
 	}
-	notifier := buildNotifier()
+	notifier := buildNotifier(os.Getenv, "brain-capture audit degraded")
 	reconcileInterval := time.Duration(envInt("BRAIN_AUDIT_RECONCILE_INTERVAL", 60)) * time.Second
 	audit.StartReconcile(ctx, central, buffer, notifier, reconcileInterval)
 	logger.Info("capture audit: loki+buffer sink", "loki", lokiURL, "reconcile_s", int(reconcileInterval.Seconds()))
@@ -366,7 +369,7 @@ func main() {
 
 	ctx := context.Background()
 	// hyperguild#157: report a symlink that appears in the brain while running.
-	go symlinkguard.Watch(ctx, brainDir, symlinkScanInterval(os.Getenv), buildNotifier())
+	go symlinkguard.Watch(ctx, brainDir, symlinkScanInterval(os.Getenv), buildNotifier(os.Getenv, "brain symlink tripwire"))
 
 	// Never fatal on an unreachable issuer (#83): on a cold cluster boot this
 	// pod can beat dex to serving and get a 502 from ingress, and exiting meant
@@ -546,7 +549,7 @@ func main() {
 		// capture already gets, plus an out-of-band alert. Wired here because
 		// brain_edit_root needs the capture plumbing anyway — that is what
 		// re-derives the static principal its gate checks.
-		mcpSrv.WithGovernanceObserver(auditSink, buildNotifier())
+		mcpSrv.WithGovernanceObserver(auditSink, buildNotifier(os.Getenv, "brain governance edit"))
 		logger.Info("capture enabled (REST + MCP tool)", "sovereign_principals", len(sovereign),
 			"governance_observer", true)
 	} else {

ingestion/cmd/server/routes_test.go

@@ -159,3 +159,16 @@ func TestBuildMuxObservesRequestsAndServesMetrics(t *testing.T) {
 	require.Equal(t, http.StatusOK, code)
 	assert.Contains(t, body, `path="GET /pending"`)
 }
+
+// hyperguild#185: an authenticated request to an unregistered path reached
+// the inner REST mux, which left Pattern empty, and the metrics label fell
+// back to the raw URL path: one Prometheus series per unique path any token
+// holder sends. It is now labelled with a fixed catch-all.
+func TestBuildMuxLabelsAnUnregisteredPathWithAFixedLabel(t *testing.T) {
+	r := testMux(t)
+	code, _ := do(t, r, "GET", "/zqrandom-185-segment", "Bearer "+routesTok)
+	require.Equal(t, http.StatusNotFound, code)
+	_, body := do(t, r, "GET", "/metrics", "")
+	assert.NotContains(t, body, "zqrandom-185-segment", "the raw path became a metrics label")
+	assert.Contains(t, body, `path="unmatched"`)
+}

ingestion/cmd/server/symlink_check_test.go

@@ -1,6 +1,9 @@
 package main
 
 import (
+	"context"
+	"net/http"
+	"net/http/httptest"
 	"os"
 	"path/filepath"
 	"strings"
@@ -74,3 +77,16 @@ func TestStartupSymlinkCheckRefusesABrainWithAFIFO(t *testing.T) {
 	require.Error(t, err)
 	assert.Contains(t, err.Error(), "classification.yaml")
 }
+
+// hyperguild#163: each alert source gets its own ntfy title.
+func TestBuildNotifierUsesTheGivenTitle(t *testing.T) {
+	var got string
+	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) { got = r.Header.Get("Title") }))
+	defer srv.Close()
+	env := map[string]string{"BRAIN_NTFY_URL": srv.URL}
+	n := buildNotifier(func(k string) string { return env[k] }, "brain symlink tripwire")
+	require.NotNil(t, n)
+	require.NoError(t, n.Notify(context.Background(), "m"))
+	assert.Equal(t, "brain symlink tripwire", got)
+	assert.Nil(t, buildNotifier(func(string) string { return "" }, "x"), "no ntfy URL, no notifier")
+}

ingestion/internal/api/handler.go

@@ -12,6 +12,7 @@ import (
 	"time"
 
 	"github.com/mathiasbq/hyperguild/ingestion/internal/brain"
+	"github.com/mathiasbq/hyperguild/ingestion/internal/brainfs"
 	"github.com/mathiasbq/hyperguild/ingestion/internal/claim"
 	"github.com/mathiasbq/hyperguild/ingestion/internal/pipeline"
 	"github.com/mathiasbq/hyperguild/ingestion/internal/search"
@@ -227,14 +228,22 @@ func writeHallNote(brainDir string, opts WriteNoteOptions) (string, error) {
 	// The directory is created only once the note is known to be writable:
 	// a refused write leaves nothing behind, not even an empty hall dir
 	// (brain#21; provenance refusal joins the envelope refusal here).
-	if err := os.MkdirAll(filepath.Dir(dest), 0o755); err != nil {
-		return "", fmt.Errorf("create hall dir: %w", err)
+	// Created through the brain root, never through a symlinked wing or
+	// hall directory (hyperguild#188).
+	rel, err := filepath.Rel(brainDir, dest)
+	if err != nil {
+		return "", fmt.Errorf("note path: %w", err)
 	}
-	if err := os.WriteFile(dest, []byte(final), 0o644); err != nil {
+	rel = filepath.ToSlash(rel)
+	bfs, err := brainfs.Open(brainDir)
+	if err != nil {
+		return "", fmt.Errorf("open brain: %w", err)
+	}
+	defer func() { _ = bfs.Close() }()
+	if err := bfs.PutRegular(rel, []byte(final)); err != nil {
 		return "", fmt.Errorf("write: %w", err)
 	}
-	rel, _ := filepath.Rel(brainDir, dest)
-	return filepath.ToSlash(rel), nil
+	return rel, nil
 }
 
 // scalarValues flattens frontmatter fields to key -> scalar value for

ingestion/internal/api/promote.go

@@ -127,18 +127,18 @@ func PromoteNote(brainDir string, opts PromoteOptions) (string, error) {
 	}
 	fm.set("promoted_at", now)
 
-	if err := os.MkdirAll(filepath.Dir(dest), 0o755); err != nil {
-		return "", fmt.Errorf("create wing dir: %w", err)
-	}
-	// Write-then-delete: the source survives any write failure.
+	// Write-then-delete: the source survives any write failure. Both go
+	// through the brain root (hyperguild#188).
 	promoted, err := StampProvenance(fm.render()+body, opts.Origin, opts.WrittenBy)
 	if err != nil {
 		return "", err
 	}
-	if err := os.WriteFile(dest, []byte(promoted), 0o644); err != nil {
+	// Created with O_EXCL: a note that appeared after the collision check
+	// above is never overwritten.
+	if err := createBrainFile(brainDir, dest, []byte(promoted)); err != nil {
 		return "", fmt.Errorf("write promoted note: %w", err)
 	}
-	if err := os.Remove(src); err != nil {
+	if err := removeBrainFile(brainDir, src); err != nil {
 		return "", fmt.Errorf("promoted note written but source removal failed: %w", err)
 	}
 
@@ -196,14 +196,12 @@ func RejectNote(brainDir string, opts RejectOptions) (string, error) {
 		fm.set("reject_reason", opts.Reason)
 	}
 
-	if err := os.MkdirAll(filepath.Dir(dest), 0o755); err != nil {
-		return "", fmt.Errorf("create rejected dir: %w", err)
-	}
-	// Write-then-delete: the source survives any write failure.
-	if err := os.WriteFile(dest, []byte(fm.render()+body), 0o644); err != nil {
+	// Write-then-delete: the source survives any write failure. Both go
+	// through the brain root (hyperguild#188).
+	if err := createBrainFile(brainDir, dest, []byte(fm.render()+body)); err != nil {
 		return "", fmt.Errorf("write rejected note: %w", err)
 	}
-	if err := os.Remove(src); err != nil {
+	if err := removeBrainFile(brainDir, src); err != nil {
 		return "", fmt.Errorf("rejected note written but source removal failed: %w", err)
 	}
 

ingestion/internal/api/promote_redirect_test.go

@@ -0,0 +1,87 @@
+package api_test
+
+import (
+	"os"
+	"path/filepath"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+
+	"github.com/mathiasbq/hyperguild/ingestion/internal/api"
+)
+
+// hyperguild#188: promote and reject wrote the destination with
+// os.MkdirAll + os.WriteFile by path, so a symlinked wing (promote) or a
+// symlinked raw/rejected (reject) redirected the note; the raw source was
+// then removed.
+func TestPromoteAndRejectRefuseASymlinkedDestinationDirectory(t *testing.T) {
+	brain := t.TempDir()
+	outside := t.TempDir()
+	raw := filepath.Join(brain, "raw")
+	require.NoError(t, os.MkdirAll(raw, 0o755))
+	require.NoError(t, os.WriteFile(filepath.Join(raw, "2026-10-05-n.md"), []byte("---\ntitle: n\n---\nbody\n"), 0o644))
+	require.NoError(t, os.MkdirAll(filepath.Join(brain, "wiki"), 0o755))
+	require.NoError(t, os.Symlink(outside, filepath.Join(brain, "wiki", "lw")))
+	require.NoError(t, os.Symlink(outside, filepath.Join(raw, "rejected")))
+
+	_, err := api.PromoteNote(brain, api.PromoteOptions{Filename: "2026-10-05-n.md", Wing: "lw", Hall: "facts"})
+	assert.Error(t, err)
+	_, err = api.RejectNote(brain, api.RejectOptions{Filename: "2026-10-05-n.md"})
+	assert.Error(t, err)
+	ents, _ := os.ReadDir(outside)
+	assert.Empty(t, ents, "a note was written outside the brain")
+	_, err = os.Stat(filepath.Join(raw, "2026-10-05-n.md"))
+	assert.NoError(t, err, "the raw source is kept when the write is refused")
+
+	require.NoError(t, os.Remove(filepath.Join(raw, "rejected")))
+	_, err = api.PromoteNote(brain, api.PromoteOptions{Filename: "2026-10-05-n.md", Wing: "w", Hall: "facts"})
+	require.NoError(t, err, "positive control: promote into a real wing")
+}
+
+// StampProvenanceFile read and rewrote the note by path (provenance.ApplyFile).
+func TestStampProvenanceFileRefusesANoteBehindASymlinkedDirectory(t *testing.T) {
+	brain := t.TempDir()
+	victim := filepath.Join(brain, "raw", "facts", "v.md")
+	require.NoError(t, os.MkdirAll(filepath.Dir(victim), 0o755))
+	require.NoError(t, os.WriteFile(victim, []byte("---\ntitle: v\n---\nuntouched\n"), 0o644))
+	require.NoError(t, os.MkdirAll(filepath.Join(brain, "wiki", "w"), 0o755))
+	require.NoError(t, os.Symlink(filepath.Join("..", "..", "raw", "facts"), filepath.Join(brain, "wiki", "w", "alias")))
+	assert.Error(t, api.StampProvenanceFile(brain, "wiki/w/alias/v.md", "static", "x"))
+	got, _ := os.ReadFile(victim)
+	assert.Equal(t, "---\ntitle: v\n---\nuntouched\n", string(got))
+
+	real := filepath.Join(brain, "wiki", "w", "facts", "r.md")
+	require.NoError(t, os.MkdirAll(filepath.Dir(real), 0o755))
+	require.NoError(t, os.WriteFile(real, []byte("---\ntitle: r\n---\nbody\n"), 0o644))
+	require.NoError(t, api.StampProvenanceFile(brain, "wiki/w/facts/r.md", "static", "x"), "positive control")
+	got, _ = os.ReadFile(real)
+	assert.Contains(t, string(got), "written_by: x")
+}
+
+// The same through an in-brain symlinked wing and raw/rejected, which
+// os.Root alone would follow.
+func TestPromoteAndRejectRefuseAnInBrainSymlinkedDestinationDirectory(t *testing.T) {
+	brain := t.TempDir()
+	raw := filepath.Join(brain, "raw")
+	require.NoError(t, os.MkdirAll(raw, 0o755))
+	require.NoError(t, os.WriteFile(filepath.Join(raw, "2026-10-05-n.md"), []byte("---\ntitle: n\n---\nbody\n"), 0o644))
+	target := filepath.Join(brain, "archive")
+	require.NoError(t, os.MkdirAll(target, 0o755))
+	require.NoError(t, os.MkdirAll(filepath.Join(brain, "wiki"), 0o755))
+	require.NoError(t, os.Symlink(filepath.Join("..", "archive"), filepath.Join(brain, "wiki", "lw")))
+	require.NoError(t, os.Symlink(filepath.Join("..", "archive"), filepath.Join(raw, "rejected")))
+
+	_, err := api.PromoteNote(brain, api.PromoteOptions{Filename: "2026-10-05-n.md", Wing: "lw", Hall: "facts"})
+	assert.Error(t, err)
+	_, err = api.RejectNote(brain, api.RejectOptions{Filename: "2026-10-05-n.md"})
+	assert.Error(t, err)
+	ents, _ := os.ReadDir(target)
+	assert.Empty(t, ents, "a note was written at the in-brain link's target")
+	_, err = os.Stat(filepath.Join(raw, "2026-10-05-n.md"))
+	assert.NoError(t, err, "the raw source is kept")
+
+	require.NoError(t, os.Remove(filepath.Join(raw, "rejected")))
+	_, err = api.RejectNote(brain, api.RejectOptions{Filename: "2026-10-05-n.md"})
+	require.NoError(t, err, "positive control: reject into a real raw/rejected")
+}

ingestion/internal/api/provenance.go

@@ -1,6 +1,10 @@
 package api
 
 import (
+	"fmt"
+	"path/filepath"
+
+	"github.com/mathiasbq/hyperguild/ingestion/internal/brainfs"
 	"github.com/mathiasbq/hyperguild/ingestion/internal/provenance"
 )
 
@@ -11,11 +15,61 @@ func StampProvenance(content, origin, writtenBy string) (string, error) {
 	return provenance.Apply(content, provenance.Stamp{Origin: origin, WrittenBy: writtenBy})
 }
 
-// StampProvenanceFile applies StampProvenance to a brain-relative note path.
+// StampProvenanceFile applies StampProvenance to a brain-relative note path,
+// read and rewritten through the brain root (hyperguild#158).
 func StampProvenanceFile(brainDir, relPath, origin, writtenBy string) error {
-	_, abs, err := resolveWithin(brainDir, relPath)
+	rel, _, err := resolveWithin(brainDir, relPath)
 	if err != nil {
 		return err
 	}
-	return provenance.ApplyFile(abs, provenance.Stamp{Origin: origin, WrittenBy: writtenBy})
+	bfs, err := brainfs.Open(brainDir)
+	if err != nil {
+		return fmt.Errorf("open brain: %w", err)
+	}
+	defer func() { _ = bfs.Close() }()
+	b, err := bfs.ReadRegular(rel)
+	if err != nil {
+		return fmt.Errorf("read for provenance: %w", err)
+	}
+	out, err := provenance.Apply(string(b), provenance.Stamp{Origin: origin, WrittenBy: writtenBy})
+	if err != nil {
+		return err
+	}
+	if out == string(b) {
+		return nil
+	}
+	if err := bfs.WriteRegular(rel, []byte(out)); err != nil {
+		return fmt.Errorf("write provenance: %w", err)
+	}
+	return nil
+}
+
+// createBrainFile creates the file at abs (inside brainDir) through the
+// brain root and fails if anything is already there.
+func createBrainFile(brainDir, abs string, data []byte) error {
+	rel, err := filepath.Rel(brainDir, abs)
+	if err != nil {
+		return err
+	}
+	bfs, err := brainfs.Open(brainDir)
+	if err != nil {
+		return fmt.Errorf("open brain: %w", err)
+	}
+	defer func() { _ = bfs.Close() }()
+	return bfs.CreateRegular(filepath.ToSlash(rel), data)
+}
+
+// removeBrainFile removes the file at abs (inside brainDir) through the
+// brain root.
+func removeBrainFile(brainDir, abs string) error {
+	rel, err := filepath.Rel(brainDir, abs)
+	if err != nil {
+		return err
+	}
+	bfs, err := brainfs.Open(brainDir)
+	if err != nil {
+		return fmt.Errorf("open brain: %w", err)
+	}
+	defer func() { _ = bfs.Close() }()
+	return bfs.Remove(filepath.ToSlash(rel))
 }

ingestion/internal/api/write_keeps_learning_test.go

@@ -0,0 +1,34 @@
+package api_test
+
+import (
+	"os"
+	"path/filepath"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+
+	"github.com/mathiasbq/hyperguild/ingestion/internal/api"
+)
+
+// hyperguild#178: an unreadable directory under wiki/ made the link check
+// fail and brain_write refuse the note, losing the learning. The note is now
+// written with its links as given.
+func TestWriteNoteKeepsTheLearningWhenTheLinkCheckCannotIndex(t *testing.T) {
+	if os.Geteuid() == 0 {
+		t.Skip("root ignores directory permissions")
+	}
+	brain := t.TempDir()
+	require.NoError(t, os.MkdirAll(filepath.Join(brain, "wiki", "w", "facts"), 0o755))
+	require.NoError(t, os.WriteFile(filepath.Join(brain, "wiki", "w", "facts", "real.md"), []byte("x"), 0o644))
+	locked := filepath.Join(brain, "wiki", "other", "locked")
+	require.NoError(t, os.MkdirAll(locked, 0o755))
+	require.NoError(t, os.Chmod(locked, 0o000))
+	t.Cleanup(func() { _ = os.Chmod(locked, 0o755) })
+
+	rel, err := api.WriteNote(brain, api.WriteNoteOptions{Wing: "w", Hall: "facts", Filename: "n", Content: "learning [[real]] and [[gone]]"})
+	require.NoError(t, err)
+	got, err := os.ReadFile(filepath.Join(brain, filepath.FromSlash(rel)))
+	require.NoError(t, err)
+	assert.Contains(t, string(got), "[[gone]]", "links kept as given when the index is partial")
+}

ingestion/internal/api/write_redirect_test.go

@@ -0,0 +1,43 @@
+package api_test
+
+import (
+	"os"
+	"path/filepath"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+
+	"github.com/mathiasbq/hyperguild/ingestion/internal/api"
+)
+
+// hyperguild#188: brain_write created a new note with os.MkdirAll +
+// os.WriteFile by path, so a symlinked wing directory redirected the note
+// elsewhere in the brain or outside it.
+func TestWriteNoteRefusesASymlinkedWing(t *testing.T) {
+	for name, target := range map[string]func(t *testing.T, brain string) string{
+		"in-brain": func(t *testing.T, brain string) string {
+			require.NoError(t, os.MkdirAll(filepath.Join(brain, "raw"), 0o755))
+			return filepath.Join("..", "raw")
+		},
+		"outside": func(t *testing.T, _ string) string { return t.TempDir() },
+	} {
+		t.Run(name, func(t *testing.T) {
+			brain := t.TempDir()
+			require.NoError(t, os.MkdirAll(filepath.Join(brain, "wiki"), 0o755))
+			link := target(t, brain)
+			require.NoError(t, os.Symlink(link, filepath.Join(brain, "wiki", "lw")))
+			_, err := api.WriteNote(brain, api.WriteNoteOptions{Wing: "lw", Hall: "facts", Filename: "n", Content: "learning"})
+			assert.Error(t, err)
+			resolved := link
+			if !filepath.IsAbs(resolved) {
+				resolved = filepath.Join(brain, "wiki", link)
+			}
+			_, serr := os.Stat(filepath.Join(resolved, "facts"))
+			assert.True(t, os.IsNotExist(serr), "a hall was created at the link's target")
+
+			_, err = api.WriteNote(brain, api.WriteNoteOptions{Wing: "w", Hall: "facts", Filename: "n", Content: "learning"})
+			require.NoError(t, err, "positive control: a real wing is written")
+		})
+	}
+}

ingestion/internal/audit/ntfy.go

@@ -13,9 +13,14 @@ import (
 type NtfyNotifier struct {
 	topicURL string
 	token    string
+	title    string
 	http     *http.Client
 }
 
+// defaultNtfyTitle is the title of a notifier built without WithTitle: the
+// capture audit's degraded-state alert, its first user.
+const defaultNtfyTitle = "brain-capture audit degraded"
+
 // NewNtfyNotifier constructs a notifier for the given ntfy topic URL
 // (e.g. https://ntfy.sh/my-topic). token is an optional bearer for
 // protected ntfy instances; it is held here and only sent in the
@@ -27,17 +32,31 @@ func NewNtfyNotifier(topicURL, token string) *NtfyNotifier {
 	return &NtfyNotifier{
 		topicURL: strings.TrimRight(topicURL, "/"),
 		token:    token,
+		title:    defaultNtfyTitle,
 		http:     &http.Client{Timeout: 10 * time.Second},
 	}
 }
 
+// WithTitle returns a copy that sends title as the ntfy Title header, so each
+// alert source (the capture audit, the symlink tripwire, governance edits)
+// is recognisable on the phone (hyperguild#163). A nil notifier (ntfy not
+// configured) stays nil.
+func (n *NtfyNotifier) WithTitle(title string) *NtfyNotifier {
+	if n == nil {
+		return nil
+	}
+	c := *n
+	c.title = title
+	return &c
+}
+
 // Notify posts a message to the ntfy topic.
 func (n *NtfyNotifier) Notify(ctx context.Context, msg string) error {
 	req, err := http.NewRequestWithContext(ctx, http.MethodPost, n.topicURL, strings.NewReader(msg))
 	if err != nil {
 		return err
 	}
-	req.Header.Set("Title", "brain-capture audit degraded")
+	req.Header.Set("Title", n.title)
 	req.Header.Set("Priority", "high")
 	req.Header.Set("Tags", "warning,brain")
 	if n.token != "" {

ingestion/internal/audit/ntfy_title_test.go

@@ -0,0 +1,29 @@
+package audit
+
+import (
+	"context"
+	"net/http"
+	"net/http/httptest"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+// hyperguild#163: every alert went out titled "brain-capture audit
+// degraded", including the symlink tripwire's and governance alerts.
+func TestNtfyNotifierSendsItsOwnTitle(t *testing.T) {
+	var got []string
+	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		got = append(got, r.Header.Get("Title"))
+	}))
+	defer srv.Close()
+	base := NewNtfyNotifier(srv.URL, "")
+	require.NoError(t, base.Notify(context.Background(), "m"))
+	require.NoError(t, base.WithTitle("brain symlink tripwire").Notify(context.Background(), "m"))
+	require.NoError(t, base.Notify(context.Background(), "m"))
+	assert.Equal(t, []string{"brain-capture audit degraded", "brain symlink tripwire", "brain-capture audit degraded"}, got,
+		"WithTitle returns a copy; the base keeps its default title")
+	var nilN *NtfyNotifier
+	assert.Nil(t, nilN.WithTitle("x"), "nil (ntfy not configured) stays nil")
+}

ingestion/internal/brain/index.go

@@ -7,8 +7,6 @@ import (
 	"fmt"
 	"io"
 	"io/fs"
-	"os"
-	"path/filepath"
 	"sort"
 	"strings"
 	"time"
@@ -32,7 +30,6 @@ func BuildWingIndex(brainDir, wing string) error {
 	if w == "" {
 		return fmt.Errorf("invalid wing %q", wing)
 	}
-	wingDir := filepath.Join(brainDir, "wiki", w)
 	// Listed and read through the brain root (hyperguild#157): a wing or
 	// hall that is a symlink is not followed, and notes are regular files.
 	bfs, err := brainfs.Open(brainDir)
@@ -63,8 +60,9 @@ func BuildWingIndex(brainDir, wing string) error {
 		fmt.Fprintf(&b, "| %s | [%s](%s/%s.md) | %s |\n", e.Hall, e.Title, e.Hall, e.Slug, e.Created)
 	}
 
-	dest := filepath.Join(wingDir, "_index.md")
-	return os.WriteFile(dest, []byte(b.String()), 0o644)
+	// Written through the brain root, never through a symlinked _index.md
+	// (hyperguild#158).
+	return bfs.PutRegular("wiki/"+w+"/_index.md", []byte(b.String()))
 }
 
 // BuildAllWingIndexes regenerates _index.md for every wing under brain/wiki/.

ingestion/internal/brain/linkcheck.go

@@ -47,7 +47,12 @@ var (
 func StripUnresolvedLinks(brainDir, content string) (string, []string, error) {
 	index, err := entryIndex(brainDir)
 	if err != nil {
-		return "", nil, err
+		// A partial index cannot tell an invented link from one into the
+		// part it could not read, so unwrap nothing, and do not refuse the
+		// write either: this runs before every brain_write, and a refused
+		// write is a lost learning (hyperguild#178).
+		slog.Warn("link check skipped: cannot index the brain", "err", err)
+		return content, nil, nil
 	}
 	if len(index) == 0 {
 		return content, nil, nil

ingestion/internal/brain/linkcheck_fallback_test.go

@@ -0,0 +1,41 @@
+package brain_test
+
+import (
+	"os"
+	"path/filepath"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+
+	"github.com/mathiasbq/hyperguild/ingestion/internal/brain"
+)
+
+// hyperguild#178: StripUnresolvedLinks runs before every brain_write and
+// brain_update. An unreadable directory under knowledge/ or wiki/ made it
+// error, the write was refused and the learning lost. When the link index
+// cannot be built, the content is now returned unchanged (no link is
+// unwrapped, none is invented) and no error stops the write.
+func TestStripUnresolvedLinksKeepsContentWhenTheIndexCannotBeBuilt(t *testing.T) {
+	if os.Geteuid() == 0 {
+		t.Skip("root ignores directory permissions")
+	}
+	b := t.TempDir()
+	require.NoError(t, os.MkdirAll(filepath.Join(b, "wiki", "w", "facts"), 0o755))
+	require.NoError(t, os.WriteFile(filepath.Join(b, "wiki", "w", "facts", "real.md"), []byte("x"), 0o644))
+	locked := filepath.Join(b, "wiki", "other", "locked")
+	require.NoError(t, os.MkdirAll(locked, 0o755))
+	require.NoError(t, os.Chmod(locked, 0o000))
+	t.Cleanup(func() { _ = os.Chmod(locked, 0o755) })
+
+	in := "learning [[real]] and [[gone]]"
+	out, unlinked, err := brain.StripUnresolvedLinks(b, in)
+	require.NoError(t, err)
+	assert.Equal(t, in, out, "content unchanged: no link unwrapped on a partial index")
+	assert.Empty(t, unlinked)
+
+	require.NoError(t, os.Chmod(locked, 0o755))
+	out, _, err = brain.StripUnresolvedLinks(b, in)
+	require.NoError(t, err)
+	assert.NotContains(t, out, "[[gone]]", "positive control: with a readable tree the strip runs")
+}

ingestion/internal/brain/tunnel.go

@@ -5,7 +5,6 @@ import (
 	"errors"
 	"fmt"
 	"io/fs"
-	"os"
 	"path"
 	"path/filepath"
 	"strings"
@@ -176,35 +175,23 @@ func logFuzzyCandidates(brainDir, sourcePath string, cs []TunnelCandidate) error
 	if len(cs) == 0 {
 		return nil
 	}
-	rawDir := filepath.Join(brainDir, "raw")
-	if err := os.MkdirAll(rawDir, 0o755); err != nil {
-		return err
-	}
-	stamp := time.Now().UTC().Format("2006-01-02")
-	path := filepath.Join(rawDir, "tunnel-candidates-"+stamp+".md")
-	existed := fileExists(path)
-	f, err := os.OpenFile(path, os.O_APPEND|os.O_CREATE|os.O_WRONLY, 0o644)
+	// Appended through the brain root, never through a symlinked raw/ or
+	// log file (hyperguild#158).
+	bfs, err := brainfs.Open(brainDir)
 	if err != nil {
-		return err
+		return fmt.Errorf("open brain: %w", err)
 	}
-	defer func() { _ = f.Close() }()
-	if !existed {
-		if _, err := f.WriteString("# Tunnel candidates " + stamp + "\n\nFuzzy cross-wing matches surfaced by AutoTunnel. Review and promote to a tunnel via `brain_tunnel` if relevant.\n\n"); err != nil {
-			return err
-		}
+	defer func() { _ = bfs.Close() }()
+	stamp := time.Now().UTC().Format("2006-01-02")
+	rel := "raw/tunnel-candidates-" + stamp + ".md"
+	var buf strings.Builder
+	if _, err := bfs.Lstat(rel); errors.Is(err, fs.ErrNotExist) {
+		buf.WriteString("# Tunnel candidates " + stamp + "\n\nFuzzy cross-wing matches surfaced by AutoTunnel. Review and promote to a tunnel via `brain_tunnel` if relevant.\n\n")
 	}
 	for _, c := range cs {
-		line := fmt.Sprintf("- `%s` ↔ `%s` (term: %q)\n", sourcePath, c.TargetPath, c.MatchedTerm)
-		if _, err := f.WriteString(line); err != nil {
-			return err
-		}
+		fmt.Fprintf(&buf, "- `%s` ↔ `%s` (term: %q)\n", sourcePath, c.TargetPath, c.MatchedTerm)
 	}
-	return nil
-}
-
-func fileExists(p string) bool {
-	_, err := os.Stat(p)
-	return err == nil
+	return bfs.AppendRegular(rel, []byte(buf.String()))
 }
 
 // WriteTunnel appends a bidirectional wikilink between sourcePath and

ingestion/internal/brain/writers_redirect_test.go

@@ -0,0 +1,52 @@
+package brain_test
+
+import (
+	"os"
+	"path/filepath"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+
+	"github.com/mathiasbq/hyperguild/ingestion/internal/brain"
+)
+
+// hyperguild#158: BuildWingIndex wrote wiki/<wing>/_index.md with
+// os.WriteFile, so a symlinked _index.md was written through.
+func TestBuildWingIndexDoesNotWriteThroughASymlinkedIndex(t *testing.T) {
+	b := t.TempDir()
+	require.NoError(t, os.MkdirAll(filepath.Join(b, "wiki", "w", "facts"), 0o755))
+	require.NoError(t, os.WriteFile(filepath.Join(b, "wiki", "w", "facts", "n.md"), []byte("---\ntitle: zqn\n---\n"), 0o644))
+	victim := filepath.Join(b, "raw", "v.md")
+	require.NoError(t, os.MkdirAll(filepath.Dir(victim), 0o755))
+	require.NoError(t, os.WriteFile(victim, []byte("untouched"), 0o644))
+	require.NoError(t, os.Symlink(filepath.Join("..", "..", "raw", "v.md"), filepath.Join(b, "wiki", "w", "_index.md")))
+	assert.Error(t, brain.BuildWingIndex(b, "w"))
+	got, _ := os.ReadFile(victim)
+	assert.Equal(t, "untouched", string(got))
+
+	require.NoError(t, os.Remove(filepath.Join(b, "wiki", "w", "_index.md")))
+	require.NoError(t, brain.BuildWingIndex(b, "w"), "positive control")
+	idx, _ := os.ReadFile(filepath.Join(b, "wiki", "w", "_index.md"))
+	assert.Contains(t, string(idx), "zqn")
+}
+
+// AutoTunnel's fuzzy-candidate log appended to raw/tunnel-candidates-*.md
+// with os.OpenFile, so a symlinked raw/ (or log file) was written through.
+func TestAutoTunnelDoesNotAppendTheCandidateLogThroughASymlinkedRaw(t *testing.T) {
+	b := t.TempDir()
+	outside := t.TempDir()
+	require.NoError(t, os.MkdirAll(filepath.Join(b, "wiki", "a", "facts"), 0o755))
+	require.NoError(t, os.MkdirAll(filepath.Join(b, "wiki", "b", "facts"), 0o755))
+	// "zq widget" matches as a substring of "zq widgets", a fuzzy candidate.
+	require.NoError(t, os.WriteFile(filepath.Join(b, "wiki", "b", "facts", "t.md"), []byte("---\ntitle: Zq Widget\n---\n"), 0o644))
+	require.NoError(t, os.Symlink(outside, filepath.Join(b, "raw")))
+	_ = brain.AutoTunnel(b, "wiki/a/facts/s.md", "about zq widgets")
+	ents, _ := os.ReadDir(outside)
+	assert.Empty(t, ents, "the candidate log was written outside the brain")
+
+	require.NoError(t, os.Remove(filepath.Join(b, "raw")))
+	require.NoError(t, brain.AutoTunnel(b, "wiki/a/facts/s.md", "about zq widgets"))
+	logs, _ := filepath.Glob(filepath.Join(b, "raw", "tunnel-candidates-*.md"))
+	assert.Len(t, logs, 1, "positive control: the fuzzy candidate is logged in the real raw/")
+}

ingestion/internal/brainfs/brainfs.go

@@ -136,6 +136,140 @@ func (b *Brain) ReadDirDirs(relDir string) ([]string, error) {
 	return names, nil
 }
 
+// PutRegular creates or replaces a regular file at a brain-relative path,
+// for creating writes (hyperguild#188, #158). Missing parent directories are
+// created one component at a time through the root, and every existing
+// component must be a real directory, so a symlinked directory cannot
+// redirect the write elsewhere in the brain or outside it. An existing file
+// is replaced only if it is regular (WriteRegular's checks); a new file is
+// created with O_EXCL and confirmed to be the file that was opened. A
+// directory swapped in after the checks is the #167 residual.
+func (b *Brain) PutRegular(rel string, data []byte) error {
+	if err := cleanRel(rel); err != nil {
+		return err
+	}
+	if err := b.mkdirReal(path.Dir(rel)); err != nil {
+		return err
+	}
+	if _, err := b.root.Lstat(rel); err == nil {
+		return b.WriteRegular(rel, data)
+	} else if !errors.Is(err, fs.ErrNotExist) {
+		return err
+	}
+	return b.createNew(rel, data)
+}
+
+// CreateRegular creates a new regular file at a brain-relative path, with
+// PutRegular's parent rules, and fails with fs.ErrExist if anything is
+// already there: for writers that must never overwrite (promote, reject).
+func (b *Brain) CreateRegular(rel string, data []byte) error {
+	if err := cleanRel(rel); err != nil {
+		return err
+	}
+	if err := b.mkdirReal(path.Dir(rel)); err != nil {
+		return err
+	}
+	return b.createNew(rel, data)
+}
+
+// createNew creates rel with O_EXCL and writes data only after confirming
+// the path is the regular file it created.
+func (b *Brain) createNew(rel string, data []byte) error {
+	f, err := b.root.OpenFile(rel, os.O_WRONLY|os.O_CREATE|os.O_EXCL|syscall.O_NOFOLLOW|syscall.O_NONBLOCK, 0o644)
+	if err != nil {
+		return err
+	}
+	defer func() { _ = f.Close() }()
+	hfi, herr := f.Stat()
+	lfi, lerr := b.root.Lstat(rel)
+	if herr != nil || lerr != nil || !lfi.Mode().IsRegular() || !os.SameFile(lfi, hfi) {
+		return fmt.Errorf("%s: changed while creating: %w", rel, ErrNotRegular)
+	}
+	if _, err := f.Write(data); err != nil {
+		return err
+	}
+	return f.Close()
+}
+
+// AppendRegular appends data to a regular file at a brain-relative path,
+// creating it (and missing parent directories, as PutRegular does) if it is
+// absent. It writes only after confirming the path is the regular file it
+// opened, so a final symlink or special file, or one swapped in, is refused.
+func (b *Brain) AppendRegular(rel string, data []byte) error {
+	if err := cleanRel(rel); err != nil {
+		return err
+	}
+	if err := b.mkdirReal(path.Dir(rel)); err != nil {
+		return err
+	}
+	if fi, err := b.root.Lstat(rel); err == nil && !fi.Mode().IsRegular() {
+		return fmt.Errorf("%s: %w", rel, ErrNotRegular)
+	} else if err != nil && !errors.Is(err, fs.ErrNotExist) {
+		return err
+	}
+	f, err := b.root.OpenFile(rel, os.O_WRONLY|os.O_APPEND|os.O_CREATE|syscall.O_NOFOLLOW|syscall.O_NONBLOCK, 0o644)
+	if err != nil {
+		return err
+	}
+	defer func() { _ = f.Close() }()
+	hfi, herr := f.Stat()
+	lfi, lerr := b.root.Lstat(rel)
+	if herr != nil || lerr != nil || !lfi.Mode().IsRegular() || !os.SameFile(lfi, hfi) {
+		return fmt.Errorf("%s: changed while opening: %w", rel, ErrNotRegular)
+	}
+	if _, err := f.Write(data); err != nil {
+		return err
+	}
+	return f.Close()
+}
+
+// Remove removes the file at a clean brain-relative path through the root,
+// refusing a path behind a symlinked directory. A final symlink is removed
+// itself, never its target.
+func (b *Brain) Remove(rel string) error {
+	if err := b.RealParent(rel); err != nil {
+		return err
+	}
+	return b.root.Remove(rel)
+}
+
+// RealParent returns ErrNotRegular unless rel is clean and every directory
+// above it is a real directory, for writers that do their own I/O (an atomic
+// rename) but must not be redirected by a symlinked directory.
+func (b *Brain) RealParent(rel string) error {
+	if err := cleanRel(rel); err != nil {
+		return err
+	}
+	return b.realDir(path.Dir(rel))
+}
+
+// mkdirReal makes sure every component of rel exists as a real directory,
+// creating missing ones through the root; an existing component that is
+// not a real directory is ErrNotRegular.
+func (b *Brain) mkdirReal(rel string) error {
+	if rel == "." {
+		return nil
+	}
+	prefix := ""
+	for _, part := range strings.Split(rel, "/") {
+		prefix = path.Join(prefix, part)
+		fi, err := b.root.Lstat(prefix)
+		if errors.Is(err, fs.ErrNotExist) {
+			if err := b.root.Mkdir(prefix, 0o755); err != nil && !errors.Is(err, fs.ErrExist) {
+				return err
+			}
+			fi, err = b.root.Lstat(prefix)
+		}
+		if err != nil {
+			return err
+		}
+		if !fi.IsDir() {
+			return fmt.Errorf("%s: component %s is not a directory: %w", rel, prefix, ErrNotRegular)
+		}
+	}
+	return nil
+}
+
 // ReadRegular reads a brain-relative path, refusing anything that is not a
 // regular file, both before the open and on the opened handle.
 func (b *Brain) ReadRegular(rel string) ([]byte, error) {

ingestion/internal/brainfs/brainfs_test.go

@@ -376,3 +376,156 @@ func TestReadAndWriteRegularRefuseAPathThatIsNotClean(t *testing.T) {
 	got, _ := os.ReadFile(filepath.Join(dir, "raw", "v.md"))
 	assert.Equal(t, "untouched", string(got))
 }
+
+// hyperguild#188: PutRegular creates or replaces a regular file through the
+// root. Missing parent directories are created; an existing component that
+// is not a real directory, a final symlink or special file, and an unclean
+// path are refused, and nothing is created at a link's target.
+func TestPutRegularCreatesOrReplacesOnlyThroughRealDirectories(t *testing.T) {
+	dir := t.TempDir()
+	outside := t.TempDir()
+	require.NoError(t, os.MkdirAll(filepath.Join(dir, "raw"), 0o755))
+	require.NoError(t, os.MkdirAll(filepath.Join(dir, "wiki"), 0o755))
+	require.NoError(t, os.Symlink(filepath.Join("..", "raw"), filepath.Join(dir, "wiki", "inwing")))
+	require.NoError(t, os.Symlink(outside, filepath.Join(dir, "wiki", "outwing")))
+	require.NoError(t, os.WriteFile(filepath.Join(dir, "raw", "v.md"), []byte("untouched"), 0o644))
+	require.NoError(t, os.MkdirAll(filepath.Join(dir, "wiki", "w"), 0o755))
+	require.NoError(t, os.Symlink(filepath.Join("..", "..", "raw", "v.md"), filepath.Join(dir, "wiki", "w", "link.md")))
+	require.NoError(t, syscall.Mkfifo(filepath.Join(dir, "wiki", "w", "f.md"), 0o644))
+	b, err := Open(dir)
+	require.NoError(t, err)
+	defer func() { _ = b.Close() }()
+
+	for _, rel := range []string{"wiki/inwing/facts/n.md", "wiki/outwing/facts/n.md", "wiki/w/link.md", "wiki/w/f.md", "wiki/w/../../raw/v.md", "/abs.md"} {
+		assert.ErrorIs(t, b.PutRegular(rel, []byte("x")), ErrNotRegular, rel)
+	}
+	ents, _ := os.ReadDir(outside)
+	assert.Empty(t, ents, "nothing created outside the brain")
+	_, err = os.Stat(filepath.Join(dir, "raw", "facts"))
+	assert.True(t, os.IsNotExist(err), "nothing created through the in-brain link")
+	got, _ := os.ReadFile(filepath.Join(dir, "raw", "v.md"))
+	assert.Equal(t, "untouched", string(got))
+
+	require.NoError(t, b.PutRegular("wiki/new/facts/n.md", []byte("one")), "positive control: create with missing parents")
+	got, _ = os.ReadFile(filepath.Join(dir, "wiki", "new", "facts", "n.md"))
+	assert.Equal(t, "one", string(got))
+	require.NoError(t, b.PutRegular("wiki/new/facts/n.md", []byte("two")), "positive control: replace")
+	got, _ = os.ReadFile(filepath.Join(dir, "wiki", "new", "facts", "n.md"))
+	assert.Equal(t, "two", string(got))
+}
+
+func TestAppendRegularCreatesOrAppendsOnlyThroughRealDirectories(t *testing.T) {
+	dir := t.TempDir()
+	outside := t.TempDir()
+	require.NoError(t, os.MkdirAll(filepath.Join(dir, "raw"), 0o755))
+	require.NoError(t, os.WriteFile(filepath.Join(dir, "raw", "v.md"), []byte("untouched"), 0o644))
+	require.NoError(t, os.Symlink(outside, filepath.Join(dir, "outdir")))
+	require.NoError(t, os.Symlink("raw", filepath.Join(dir, "indir")))
+	require.NoError(t, os.Symlink(filepath.Join("raw", "v.md"), filepath.Join(dir, "log.md")))
+	require.NoError(t, syscall.Mkfifo(filepath.Join(dir, "f.md"), 0o644))
+	b, err := Open(dir)
+	require.NoError(t, err)
+	defer func() { _ = b.Close() }()
+
+	for _, rel := range []string{"outdir/l.md", "indir/v.md", "log.md", "f.md", "raw/../log.md"} {
+		assert.ErrorIs(t, b.AppendRegular(rel, []byte("x")), ErrNotRegular, rel)
+	}
+	ents, _ := os.ReadDir(outside)
+	assert.Empty(t, ents)
+	got, _ := os.ReadFile(filepath.Join(dir, "raw", "v.md"))
+	assert.Equal(t, "untouched", string(got))
+
+	require.NoError(t, b.AppendRegular("logs/a.md", []byte("one\n")), "positive control: create")
+	require.NoError(t, b.AppendRegular("logs/a.md", []byte("two\n")), "positive control: append")
+	got, _ = os.ReadFile(filepath.Join(dir, "logs", "a.md"))
+	assert.Equal(t, "one\ntwo\n", string(got))
+}
+
+func TestRealParentRefusesASymlinkedDirectoryOrUncleanPath(t *testing.T) {
+	dir := t.TempDir()
+	require.NoError(t, os.MkdirAll(filepath.Join(dir, "raw"), 0o755))
+	require.NoError(t, os.MkdirAll(filepath.Join(dir, "wiki"), 0o755))
+	require.NoError(t, os.Symlink(filepath.Join("..", "raw"), filepath.Join(dir, "wiki", "alias")))
+	b, err := Open(dir)
+	require.NoError(t, err)
+	defer func() { _ = b.Close() }()
+	assert.ErrorIs(t, b.RealParent("wiki/alias/x.md"), ErrNotRegular)
+	assert.ErrorIs(t, b.RealParent("wiki/../raw/x.md"), ErrNotRegular)
+	assert.NoError(t, b.RealParent("wiki/x.md"), "positive control")
+}
+
+// cleanRel must refuse an unclean path on its own: here the ".." resolves,
+// after a symlinked directory, to a real regular file, so only the clean
+// check stands between the call and that file.
+func TestAppendRegularRefusesAnUncleanPathThatResolvesToARealFile(t *testing.T) {
+	dir := t.TempDir()
+	require.NoError(t, os.MkdirAll(filepath.Join(dir, "raw", "keep"), 0o755))
+	require.NoError(t, os.WriteFile(filepath.Join(dir, "raw", "v.md"), []byte("untouched"), 0o644))
+	require.NoError(t, os.Symlink(filepath.Join("raw", "keep"), filepath.Join(dir, "indir")))
+	b, err := Open(dir)
+	require.NoError(t, err)
+	defer func() { _ = b.Close() }()
+	assert.ErrorIs(t, b.AppendRegular("indir/../v.md", []byte("x")), ErrNotRegular)
+	assert.ErrorIs(t, b.PutRegular("indir/../v.md", []byte("x")), ErrNotRegular)
+	got, _ := os.ReadFile(filepath.Join(dir, "raw", "v.md"))
+	assert.Equal(t, "untouched", string(got))
+}
+
+func TestRemoveRefusesAPathBehindASymlinkedDirectoryAndRemovesOnlyTheLink(t *testing.T) {
+	dir := t.TempDir()
+	require.NoError(t, os.MkdirAll(filepath.Join(dir, "raw"), 0o755))
+	require.NoError(t, os.WriteFile(filepath.Join(dir, "raw", "v.md"), []byte("keep"), 0o644))
+	require.NoError(t, os.MkdirAll(filepath.Join(dir, "wiki"), 0o755))
+	require.NoError(t, os.Symlink(filepath.Join("..", "raw"), filepath.Join(dir, "wiki", "alias")))
+	require.NoError(t, os.Symlink(filepath.Join("..", "raw", "v.md"), filepath.Join(dir, "wiki", "link.md")))
+	require.NoError(t, os.WriteFile(filepath.Join(dir, "wiki", "n.md"), []byte("n"), 0o644))
+	b, err := Open(dir)
+	require.NoError(t, err)
+	defer func() { _ = b.Close() }()
+
+	assert.ErrorIs(t, b.Remove("wiki/alias/v.md"), ErrNotRegular)
+	_, err = os.Stat(filepath.Join(dir, "raw", "v.md"))
+	assert.NoError(t, err, "the file behind the symlinked directory is kept")
+	require.NoError(t, b.Remove("wiki/link.md"))
+	_, err = os.Stat(filepath.Join(dir, "raw", "v.md"))
+	assert.NoError(t, err, "removing a final symlink never removes its target")
+	require.NoError(t, b.Remove("wiki/n.md"), "positive control")
+	_, err = os.Stat(filepath.Join(dir, "wiki", "n.md"))
+	assert.True(t, os.IsNotExist(err))
+}
+
+// CreateRegular is the only write path for promote and reject: it creates
+// missing parents through the root, refuses an in-brain symlinked parent and
+// an unclean path, and never replaces anything already there (fs.ErrExist,
+// content unchanged), including a dangling link.
+func TestCreateRegularCreatesOnlyNewFilesThroughRealDirectories(t *testing.T) {
+	dir := t.TempDir()
+	require.NoError(t, os.MkdirAll(filepath.Join(dir, "raw", "keep"), 0o755))
+	require.NoError(t, os.MkdirAll(filepath.Join(dir, "wiki"), 0o755))
+	require.NoError(t, os.Symlink(filepath.Join("..", "raw"), filepath.Join(dir, "wiki", "inwing")))
+	require.NoError(t, os.WriteFile(filepath.Join(dir, "raw", "v.md"), []byte("untouched"), 0o644))
+	require.NoError(t, os.Symlink(filepath.Join("raw", "keep"), filepath.Join(dir, "indir")))
+	require.NoError(t, os.WriteFile(filepath.Join(dir, "wiki", "exists.md"), []byte("original"), 0o644))
+	require.NoError(t, os.Symlink("nowhere.md", filepath.Join(dir, "wiki", "dangling.md")))
+	b, err := Open(dir)
+	require.NoError(t, err)
+	defer func() { _ = b.Close() }()
+
+	assert.ErrorIs(t, b.CreateRegular("wiki/inwing/facts/n.md", []byte("x")), ErrNotRegular)
+	_, err = os.Stat(filepath.Join(dir, "raw", "facts"))
+	assert.True(t, os.IsNotExist(err), "nothing created through the in-brain link")
+	assert.ErrorIs(t, b.CreateRegular("indir/../v.md", []byte("x")), ErrNotRegular)
+	got, _ := os.ReadFile(filepath.Join(dir, "raw", "v.md"))
+	assert.Equal(t, "untouched", string(got))
+
+	assert.ErrorIs(t, b.CreateRegular("wiki/exists.md", []byte("x")), fs.ErrExist)
+	got, _ = os.ReadFile(filepath.Join(dir, "wiki", "exists.md"))
+	assert.Equal(t, "original", string(got))
+	assert.ErrorIs(t, b.CreateRegular("wiki/dangling.md", []byte("x")), fs.ErrExist)
+	_, err = os.Stat(filepath.Join(dir, "wiki", "nowhere.md"))
+	assert.True(t, os.IsNotExist(err), "nothing created at the dangling link's target")
+
+	require.NoError(t, b.CreateRegular("wiki/new/facts/n.md", []byte("one")), "positive control: create with missing parents")
+	got, _ = os.ReadFile(filepath.Join(dir, "wiki", "new", "facts", "n.md"))
+	assert.Equal(t, "one", string(got))
+}

ingestion/internal/metrics/metrics.go

@@ -83,8 +83,9 @@ func (r *Registry) Observe(path, status string, d time.Duration) {
 
 // Middleware wraps next, observing every request's duration + status.
 // The metric label `path` uses the request's Pattern (Go 1.22+ ServeMux),
-// falling back to the URL path if no Pattern is set. Pattern keeps
-// cardinality bounded (one series per route, not one per unique URL).
+// or the fixed label "unmatched" if no Pattern is set: falling back to the
+// raw URL path gave any caller one series per unique path (hyperguild#185).
+// Pattern keeps cardinality bounded (one series per route).
 func (r *Registry) Middleware(next http.Handler) http.Handler {
 	return http.HandlerFunc(func(w http.ResponseWriter, req *http.Request) {
 		rec := &statusRecorder{ResponseWriter: w, code: http.StatusOK}
@@ -92,7 +93,7 @@ func (r *Registry) Middleware(next http.Handler) http.Handler {
 		next.ServeHTTP(rec, req)
 		path := req.Pattern
 		if path == "" {
-			path = req.URL.Path
+			path = "unmatched"
 		}
 		r.Observe(path, statusClass(rec.code), time.Since(start))
 	})

ingestion/internal/metrics/metrics_test.go

@@ -71,11 +71,16 @@ func TestMiddleware_RecordsTiming(t *testing.T) {
 	t.Parallel()
 
 	r := New()
-	handler := r.Middleware(http.HandlerFunc(func(w http.ResponseWriter, _ *http.Request) {
+	// Routed through a ServeMux, as in production: the mux sets the
+	// request's Pattern, which is the label (an unrouted request is
+	// "unmatched", hyperguild#185).
+	mux := http.NewServeMux()
+	mux.HandleFunc("/query", func(w http.ResponseWriter, _ *http.Request) {
 		time.Sleep(2 * time.Millisecond)
 		w.WriteHeader(http.StatusOK)
 		_, _ = io.WriteString(w, "ok")
-	}))
+	})
+	handler := r.Middleware(mux)
 
 	srv := httptest.NewServer(handler)
 	defer srv.Close()
@@ -117,3 +122,19 @@ func TestStatusRecorder_DefaultsTo200(t *testing.T) {
 		t.Errorf("code %d, want 200", rec.Code)
 	}
 }
+
+// A request with no matched Pattern is labelled "unmatched", never with its
+// raw URL path (unbounded cardinality, hyperguild#185).
+func TestMiddleware_LabelsAnUnmatchedRequestWithAFixedLabel(t *testing.T) {
+	r := New()
+	h := r.Middleware(http.NotFoundHandler())
+	h.ServeHTTP(httptest.NewRecorder(), httptest.NewRequest("GET", "/zqrandom-185-unit", nil))
+	rec := httptest.NewRecorder()
+	r.Handler().ServeHTTP(rec, httptest.NewRequest("GET", "/metrics", nil))
+	if strings.Contains(rec.Body.String(), "zqrandom-185-unit") {
+		t.Errorf("the raw path became a metrics label:\n%s", rec.Body.String())
+	}
+	if !strings.Contains(rec.Body.String(), `path="unmatched"`) {
+		t.Errorf("no unmatched label:\n%s", rec.Body.String())
+	}
+}

ingestion/internal/notes/edit_redirect_test.go

@@ -0,0 +1,36 @@
+package notes
+
+import (
+	"os"
+	"path/filepath"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+// hyperguild#188/#173: brain_edit's atomic rename must not be redirected by
+// a symlinked directory inside the brain.
+func TestEditRefusesANoteBehindASymlinkedDirectory(t *testing.T) {
+	b := t.TempDir()
+	// Edit refuses a tree that is not the sync source before any path
+	// check, so the test needs a .git to reach the symlink refusal.
+	require.NoError(t, os.MkdirAll(filepath.Join(b, ".git"), 0o755))
+	victim := filepath.Join(b, "raw", "facts", "v.md")
+	require.NoError(t, os.MkdirAll(filepath.Dir(victim), 0o755))
+	require.NoError(t, os.WriteFile(victim, []byte("old text\n"), 0o644))
+	require.NoError(t, os.MkdirAll(filepath.Join(b, "wiki", "w"), 0o755))
+	require.NoError(t, os.Symlink(filepath.Join("..", "..", "raw", "facts"), filepath.Join(b, "wiki", "w", "alias")))
+	_, err := Edit(b, "wiki/w/alias/v.md", "old text", "new text", ScopeNotes)
+	assert.Error(t, err)
+	got, _ := os.ReadFile(victim)
+	assert.Equal(t, "old text\n", string(got))
+
+	real := filepath.Join(b, "wiki", "w", "facts", "r.md")
+	require.NoError(t, os.MkdirAll(filepath.Dir(real), 0o755))
+	require.NoError(t, os.WriteFile(real, []byte("old text\n"), 0o644))
+	_, err = Edit(b, "wiki/w/facts/r.md", "old text", "new text", ScopeNotes)
+	require.NoError(t, err, "positive control: a note in a real directory is edited")
+	got, _ = os.ReadFile(real)
+	assert.Equal(t, "new text\n", string(got))
+}

ingestion/internal/provenance/provenance.go

@@ -28,7 +28,6 @@ import (
 	"context"
 	"errors"
 	"fmt"
-	"os"
 	"regexp"
 	"strings"
 
@@ -102,25 +101,6 @@ func Apply(content string, s Stamp) (string, error) {
 	return out, nil
 }
 
-// ApplyFile applies the stamp to the note at absPath in place.
-func ApplyFile(absPath string, s Stamp) error {
-	b, err := os.ReadFile(absPath)
-	if err != nil {
-		return fmt.Errorf("read for provenance: %w", err)
-	}
-	out, err := Apply(string(b), s)
-	if err != nil {
-		return err
-	}
-	if out == string(b) {
-		return nil
-	}
-	if err := os.WriteFile(absPath, []byte(out), 0o644); err != nil {
-		return fmt.Errorf("write provenance: %w", err)
-	}
-	return nil
-}
-
 // plainGroups keeps the provably plain key groups of a frontmatter block.
 func plainGroups(block string) string {
 	lines := strings.Split(strings.TrimSuffix(block, "\n"), "\n")

ingestion/internal/symlinkguard/symlinkguard_test.go

@@ -381,18 +381,19 @@ func TestWatchQueueIsBoundedDuringAnOutage(t *testing.T) {
 		require.Eventually(t, func() bool { _, err := os.Lstat(link); return os.IsNotExist(err) }, 2*time.Second, 2*time.Millisecond)
 	}
 	n.down.Store(false)
-	require.Eventually(t, func() bool { return n.count() >= 1 }, 2*time.Second, 5*time.Millisecond)
-	time.Sleep(100 * time.Millisecond)
-	assert.LessOrEqual(t, n.count(), maxPending+1, "queued alerts plus at most one suppression summary")
-	n.mu.Lock()
-	defer n.mu.Unlock()
-	found := false
-	for _, m := range n.msgs {
-		if strings.Contains(m, "suppressed") {
-			found = true
+	// Synchronise on the summary being delivered (hyperguild#193: a fixed
+	// sleep flaked under load); once it is, the queue has been flushed.
+	require.Eventually(t, func() bool {
+		n.mu.Lock()
+		defer n.mu.Unlock()
+		for _, m := range n.msgs {
+			if strings.Contains(m, "suppressed") {
+				return true
+			}
 		}
-	}
-	assert.True(t, found, "suppressed alerts are counted in a summary")
+		return false
+	}, 10*time.Second, 5*time.Millisecond, "suppressed alerts are counted in a summary")
+	assert.LessOrEqual(t, n.count(), maxPending+1, "queued alerts plus at most one suppression summary")
 }
 
 // Within the bound, every alert queued during an outage is delivered after
@@ -411,11 +412,21 @@ func TestWatchDeliversEveryQueuedAlertAfterAShortOutage(t *testing.T) {
 		require.Eventually(t, func() bool { _, err := os.Lstat(link); return os.IsNotExist(err) }, 2*time.Second, 2*time.Millisecond)
 	}
 	n.down.Store(false)
-	require.Eventually(t, func() bool { return n.count() == 3 }, 2*time.Second, 5*time.Millisecond)
+	require.Eventually(t, func() bool { return n.count() >= 3 }, 10*time.Second, 5*time.Millisecond)
 	n.mu.Lock()
 	defer n.mu.Unlock()
-	for i, name := range []string{"qa", "qb", "qc"} {
-		assert.Contains(t, n.msgs[i], strconv.Quote(name))
+	// Each removal delivered exactly once, in any order: the outage ends
+	// asynchronously, possibly mid-flush, so a later item can send before an
+	// earlier one (hyperguild#193). Order is not what this test is about.
+	assert.Len(t, n.msgs, 3)
+	for _, name := range []string{"qa", "qb", "qc"} {
+		hits := 0
+		for _, m := range n.msgs {
+			if strings.Contains(m, strconv.Quote(name)) {
+				hits++
+			}
+		}
+		assert.Equal(t, 1, hits, "%s delivered exactly once", name)
 	}
 }
 
@@ -457,29 +468,30 @@ func TestWatchAccountsForEveryRemovalDuringAnOutage(t *testing.T) {
 		require.Eventually(t, func() bool { _, err := os.Lstat(link); return os.IsNotExist(err) }, 2*time.Second, 1*time.Millisecond)
 	}
 	n.down.Store(false)
-	require.Eventually(t, func() bool {
+	// Synchronise on the record being complete, not on a fixed sleep after
+	// the first summary (hyperguild#193): sum every "removed N" alert and
+	// every suppression count until they account for all plants.
+	account := func() (delivered, counted int) {
 		n.mu.Lock()
 		defer n.mu.Unlock()
 		for _, m := range n.msgs {
-			if strings.Contains(m, "suppressed") {
-				return true
+			var k int
+			if i := strings.Index(m, "removed "); i >= 0 && strings.Contains(m, "symlink(s)") {
+				if _, err := fmt.Sscanf(m[i+len("removed "):], "%d", &k); err == nil {
+					delivered += k
+				}
+			}
+			if i := strings.Index(m, "): "); i >= 0 && strings.Contains(m, "suppressed") {
+				if _, err := fmt.Sscanf(m[i+3:], "%d", &k); err == nil {
+					counted += k
+				}
 			}
 		}
-		return false
-	}, 2*time.Second, 5*time.Millisecond)
-	time.Sleep(50 * time.Millisecond)
-	n.mu.Lock()
-	defer n.mu.Unlock()
-	delivered, counted := 0, 0
-	for _, m := range n.msgs {
-		if strings.Contains(m, "removed 1 symlink(s)") {
-			delivered++
-		}
-		if i := strings.Index(m, "): "); i >= 0 && strings.Contains(m, "suppressed") {
-			_, _ = fmt.Sscanf(m[i+3:], "%d", &counted)
-		}
+		return delivered, counted
 	}
-	assert.Equal(t, plants, delivered+counted, "delivered %d + counted %d must equal %d removals", delivered, counted, plants)
+	require.Eventually(t, func() bool { d, c := account(); return d+c >= plants }, 10*time.Second, 5*time.Millisecond)
+	d, c := account()
+	assert.Equal(t, plants, d+c, "delivered %d + counted %d must equal %d removals", d, c, plants)
 }
 
 // A poison message is still dropped (others send while it fails), and the

ingestion/internal/watcher/watcher.go

@@ -9,6 +9,7 @@ import (
 	"os"
 	"path/filepath"
 	"strings"
+	"sync"
 	"time"
 	"unicode"
 
@@ -21,11 +22,19 @@ type Config struct {
 	BrainDir string
 	Interval time.Duration
 	Pipeline pipeline.Config
+
+	// stuck remembers notes that were ingested but could neither be removed
+	// from raw/ nor marked (e.g. a read-only raw/), so later polls skip them
+	// instead of ingesting them again. In memory only: a restart retries once.
+	stuck *sync.Map
 }
 
 // Start launches the watcher in a background goroutine.
 // It returns immediately. The watcher stops when ctx is cancelled.
 func Start(ctx context.Context, cfg Config) {
+	if cfg.stuck == nil {
+		cfg.stuck = &sync.Map{}
+	}
 	go func() {
 		ticker := time.NewTicker(cfg.Interval)
 		defer ticker.Stop()
@@ -108,6 +117,12 @@ func processDir(ctx context.Context, cfg Config, date string) []error {
 			return nil
 		}
 
+		if cfg.stuck != nil {
+			if _, skip := cfg.stuck.Load(path); skip {
+				return nil
+			}
+		}
+
 		// Skip files that have already been processed or permanently failed.
 		if _, err := os.Stat(path + ".processed"); err == nil {
 			return nil
@@ -127,9 +142,12 @@ func processDir(ctx context.Context, cfg Config, date string) []error {
 	return errs
 }
 
-// processFile reads a file, calls pipeline.Run, copies it to processed/ or failed/,
-// and writes a marker file next to the original so the watcher skips it next poll.
-// The original file is never deleted, keeping Syncthing-connected vaults (e.g. Obsidian) intact.
+// processFile reads a file, calls pipeline.Run, and archives it into processed/
+// or failed/. The original is then removed from raw/ so that raw/ only ever
+// holds unprocessed input (inbox zero). The removal syncs to Syncthing peers;
+// the archive copy under raw/processed/ or raw/failed/ is what they keep. A
+// marker is written next to the original only if the removal fails, so a
+// stuck file is not re-ingested every poll.
 func processFile(ctx context.Context, cfg Config, root *os.Root, rawDir, path, date string) error {
 	filename := filepath.Base(path)
 	source := deriveSource(filename)
@@ -138,6 +156,10 @@ func processFile(ctx context.Context, cfg Config, root *os.Root, rawDir, path, d
 		return fmt.Errorf("relative path: %w", err)
 	}
 
+	before, err := root.Lstat(rel)
+	if err != nil {
+		return fmt.Errorf("stat before ingest: %w", err)
+	}
 	content, err := extract.TextIn(root, rel)
 	if err != nil {
 		return fmt.Errorf("extract text: %w", err)
@@ -154,9 +176,11 @@ func processFile(ctx context.Context, cfg Config, root *os.Root, rawDir, path, d
 		if cpErr := copyFromRoot(root, rel, dest); cpErr != nil {
 			return fmt.Errorf("copy to failed: %w", cpErr)
 		}
-		if mkErr := os.WriteFile(path+".failed", []byte(runErr.Error()), 0o644); mkErr != nil {
-			slog.Error("watcher: failed to write .failed marker", "error", mkErr)
+		if changedSince(root, rel, before) {
+			slog.Warn("watcher: note changed during ingest; leaving it in raw/ for the next poll", "file", filename)
+			return nil
 		}
+		retire(cfg, root, rel, path, ".failed", runErr.Error())
 
 		slog.Warn("watcher: file failed", "file", filename, "error", runErr)
 
@@ -182,14 +206,45 @@ func processFile(ctx context.Context, cfg Config, root *os.Root, rawDir, path, d
 	if err := copyFromRoot(root, rel, dest); err != nil {
 		return fmt.Errorf("copy to processed: %w", err)
 	}
-	if err := os.WriteFile(path+".processed", []byte(date), 0o644); err != nil {
-		slog.Error("watcher: failed to write .processed marker", "error", err)
+	if changedSince(root, rel, before) {
+		slog.Warn("watcher: note changed during ingest; leaving it in raw/ for the next poll", "file", filename)
+		return nil
 	}
+	retire(cfg, root, rel, path, ".processed", date)
 
 	slog.Info("watcher: file processed", "file", filename, "source", source)
 	return nil
 }
 
+// changedSince reports whether the note at rel differs (size or mtime) from
+// before. A note replaced mid-ingest (Syncthing) was extracted from older
+// content than it now holds, so it must not be removed. Limits: a same-size
+// rewrite with a restored mtime is not detected (the new bytes then survive
+// only in the archive copy), nor a change between this check and Remove.
+func changedSince(root *os.Root, rel string, before os.FileInfo) bool {
+	now, err := root.Lstat(rel)
+	if err != nil {
+		return true
+	}
+	return now.Size() != before.Size() || !now.ModTime().Equal(before.ModTime())
+}
+
+// retire removes an archived original from raw/ (inbox zero). If the removal
+// fails it falls back to a marker file so the watcher still skips the file.
+func retire(cfg Config, root *os.Root, rel, path, markerSuffix, markerBody string) {
+	rmErr := root.Remove(rel)
+	if rmErr == nil {
+		return
+	}
+	slog.Error("watcher: failed to remove archived original; writing marker", "file", rel, "error", rmErr)
+	if err := os.WriteFile(path+markerSuffix, []byte(markerBody), 0o644); err != nil {
+		slog.Error("watcher: failed to write marker; skipping this note until restart", "file", rel, "error", err)
+		if cfg.stuck != nil {
+			cfg.stuck.Store(path, struct{}{})
+		}
+	}
+}
+
 // deriveSource turns a filename into a human-readable source name.
 // "shape-up-book.md" → "Shape Up Book"
 func deriveSource(filename string) string {

ingestion/internal/watcher/watcher_test.go

@@ -89,13 +89,12 @@ func TestStart_ProcessesFile(t *testing.T) {
 	}
 	require.True(t, found, "file should be copied to processed/")
 
-	// Original file should still exist (copy, not move — keeps Obsidian vault intact).
+	// Inbox zero: once archived, the original leaves raw/ and no marker is
+	// left behind, so what remains in raw/ is exactly the unprocessed set.
 	_, err := os.Stat(rawFile)
-	assert.NoError(t, err, "original file should remain in raw/")
-
-	// A .processed marker should exist next to the original.
+	assert.ErrorIs(t, err, os.ErrNotExist, "original should be removed from raw/ once archived")
 	_, err = os.Stat(rawFile + ".processed")
-	assert.NoError(t, err, ".processed marker should be written")
+	assert.ErrorIs(t, err, os.ErrNotExist, "no .processed marker: the archive copy is the record")
 
 	// Wiki page should exist.
 	wikiPath := filepath.Join(brainDir, "wiki", "sources", "shape-up-book.md")
@@ -142,13 +141,11 @@ func TestStart_MovesToFailedOnError(t *testing.T) {
 	}
 	require.True(t, found, "file should be copied to failed/")
 
-	// Original file should still exist (copy, not move — keeps Obsidian vault intact).
+	// Inbox zero: a quarantined original leaves raw/ too, no marker beside it.
 	_, err := os.Stat(rawFile)
-	assert.NoError(t, err, "original file should remain in raw/")
-
-	// A .failed marker should exist next to the original.
+	assert.ErrorIs(t, err, os.ErrNotExist, "original should be removed from raw/ once quarantined")
 	_, err = os.Stat(rawFile + ".failed")
-	assert.NoError(t, err, ".failed marker should be written")
+	assert.ErrorIs(t, err, os.ErrNotExist, "no .failed marker: failed/ is the record")
 
 	// log.md should contain a watcher error entry.
 	logContent, err := os.ReadFile(filepath.Join(brainDir, "log.md"))
@@ -390,3 +387,86 @@ func TestProcessDir_DoesNotHangUnderAFIFOSwapRace(t *testing.T) {
 		t.Fatalf("the watcher hung on a swapped-in FIFO after %d iterations", iters.Load())
 	}
 }
+
+// A note whose removal AND marker write both fail (read-only raw/) must not be
+// re-ingested on every poll: each pass would write another archive copy.
+func TestProcessDir_DoesNotReingestANoteItCannotRetire(t *testing.T) {
+	brainDir := setupBrainDir(t)
+	rawDir := filepath.Join(brainDir, "raw")
+	require.NoError(t, os.WriteFile(filepath.Join(rawDir, "stuck.md"), []byte("Content."), 0o644))
+	// processed/ must exist and stay writable; only raw/ itself is locked.
+	require.NoError(t, os.MkdirAll(filepath.Join(rawDir, "processed"), 0o755))
+	require.NoError(t, os.Chmod(rawDir, 0o555))
+	t.Cleanup(func() { _ = os.Chmod(rawDir, 0o755) })
+
+	var calls atomic.Int32
+	cfg := Config{
+		BrainDir: brainDir,
+		Pipeline: pipeline.Config{
+			Complete: func(ctx context.Context, s, u string) (string, error) {
+				calls.Add(1)
+				return successComplete(pipeline.RawPage{Title: "Stuck", Type: "source", Subtype: "article", Content: "x\n"})(ctx, s, u)
+			},
+			Schema: "# Schema",
+		},
+		stuck: &sync.Map{},
+	}
+	for i := 0; i < 3; i++ {
+		processDir(context.Background(), cfg, "2026-10-19")
+	}
+	assert.Equal(t, int32(1), calls.Load(), "a note that cannot be retired is ingested once, not once per poll")
+}
+
+// If the archive copy cannot be written, the original is the only copy left:
+// it must stay in raw/.
+func TestProcessDir_KeepsTheOriginalWhenTheArchiveCopyFails(t *testing.T) {
+	brainDir := setupBrainDir(t)
+	rawDir := filepath.Join(brainDir, "raw")
+	note := filepath.Join(rawDir, "keep-me.md")
+	require.NoError(t, os.WriteFile(note, []byte("Content."), 0o644))
+	// The dated archive dir exists but is read-only: MkdirAll succeeds, the
+	// copy itself (os.Create) fails.
+	dated := filepath.Join(rawDir, "processed", "2026-10-19")
+	require.NoError(t, os.MkdirAll(dated, 0o755))
+	require.NoError(t, os.Chmod(dated, 0o555))
+	t.Cleanup(func() { _ = os.Chmod(dated, 0o755) })
+
+	cfg := Config{
+		BrainDir: brainDir,
+		Pipeline: pipeline.Config{
+			Complete: successComplete(pipeline.RawPage{Title: "Keep Me", Type: "source", Subtype: "article", Content: "x\n"}),
+			Schema:   "# Schema",
+		},
+	}
+	errs := processDir(context.Background(), cfg, "2026-10-19")
+
+	assert.NotEmpty(t, errs, "the failed archive is reported")
+	_, err := os.Stat(note)
+	assert.NoError(t, err, "original stays in raw/ when it could not be archived")
+}
+
+// If the note is replaced (e.g. by Syncthing) while it is being ingested, the
+// wiki page was extracted from the old content; removing the original would
+// leave the new content only in the archive and never re-ingest it. Observes
+// size/mtime change only: a same-size rewrite with a restored mtime is not caught.
+func TestProcessDir_KeepsANoteThatChangedWhileItWasBeingIngested(t *testing.T) {
+	brainDir := setupBrainDir(t)
+	note := filepath.Join(brainDir, "raw", "edited.md")
+	require.NoError(t, os.WriteFile(note, []byte("old"), 0o644))
+
+	cfg := Config{
+		BrainDir: brainDir,
+		Pipeline: pipeline.Config{
+			Complete: func(ctx context.Context, s, u string) (string, error) {
+				require.NoError(t, os.WriteFile(note, []byte("newer and longer content"), 0o644))
+				return successComplete(pipeline.RawPage{Title: "Edited", Type: "source", Subtype: "article", Content: "x\n"})(ctx, s, u)
+			},
+			Schema: "# Schema",
+		},
+	}
+	processDir(context.Background(), cfg, "2026-10-19")
+
+	got, err := os.ReadFile(note)
+	require.NoError(t, err, "a note that changed during ingest must stay in raw/")
+	assert.Equal(t, "newer and longer content", string(got))
+}

ingestion/internal/wiki/index.go

@@ -3,8 +3,6 @@ package wiki
 
 import (
 	"fmt"
-	"os"
-	"path/filepath"
 	"strings"
 
 	"github.com/mathiasbq/hyperguild/ingestion/internal/brainfs"
@@ -50,8 +48,8 @@ func RebuildIndex(brainDir, date string) error {
 		sb.WriteString("\n")
 	}
 
-	dest := filepath.Join(brainDir, "wiki", "index.md")
-	return os.WriteFile(dest, []byte(sb.String()), 0o644)
+	// Written through the brain root, never through a symlink (#158).
+	return bfs.PutRegular("wiki/index.md", []byte(sb.String()))
 }
 
 // pageFirstSentence reads the page through the brain root, regular files

ingestion/internal/wiki/log.go

@@ -3,8 +3,7 @@ package wiki
 
 import (
 	"fmt"
-	"os"
-	"path/filepath"
+	"github.com/mathiasbq/hyperguild/ingestion/internal/brainfs"
 	"strings"
 )
 
@@ -27,14 +26,14 @@ func AppendLog(brainDir, source string, pages, warnings []string, date string) e
 	}
 	sb.WriteString("\n")
 
-	logPath := filepath.Join(brainDir, "log.md")
-	f, err := os.OpenFile(logPath, os.O_APPEND|os.O_CREATE|os.O_WRONLY, 0o644)
+	// Appended through the brain root, never through a symlink (#158).
+	bfs, err := brainfs.Open(brainDir)
 	if err != nil {
-		return fmt.Errorf("open log: %w", err)
+		return fmt.Errorf("open brain: %w", err)
 	}
-	if _, err = f.WriteString(sb.String()); err != nil {
-		f.Close() //nolint:errcheck
+	defer func() { _ = bfs.Close() }()
+	if err := bfs.AppendRegular("log.md", []byte(sb.String())); err != nil {
 		return fmt.Errorf("write log: %w", err)
 	}
-	return f.Close()
+	return nil
 }

ingestion/internal/wiki/writers_redirect_test.go

@@ -0,0 +1,35 @@
+package wiki
+
+import (
+	"os"
+	"path/filepath"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+// hyperguild#158: RebuildIndex wrote wiki/index.md and AppendLog appended
+// log.md with os.WriteFile / os.OpenFile, so a symlinked file was written
+// through.
+func TestRebuildIndexAndAppendLogDoNotWriteThroughSymlinks(t *testing.T) {
+	b := t.TempDir()
+	require.NoError(t, os.MkdirAll(filepath.Join(b, "wiki", "concepts"), 0o755))
+	victim := filepath.Join(b, "raw", "v.md")
+	require.NoError(t, os.MkdirAll(filepath.Dir(victim), 0o755))
+	require.NoError(t, os.WriteFile(victim, []byte("untouched"), 0o644))
+	require.NoError(t, os.Symlink(filepath.Join("..", "raw", "v.md"), filepath.Join(b, "wiki", "index.md")))
+	require.NoError(t, os.Symlink(filepath.Join("raw", "v.md"), filepath.Join(b, "log.md")))
+
+	assert.Error(t, RebuildIndex(b, "2026-10-05"))
+	assert.Error(t, AppendLog(b, "src", []string{"p"}, nil, "2026-10-05"))
+	got, _ := os.ReadFile(victim)
+	assert.Equal(t, "untouched", string(got))
+
+	require.NoError(t, os.Remove(filepath.Join(b, "wiki", "index.md")))
+	require.NoError(t, os.Remove(filepath.Join(b, "log.md")))
+	require.NoError(t, RebuildIndex(b, "2026-10-05"), "positive control")
+	require.NoError(t, AppendLog(b, "src", []string{"p"}, nil, "2026-10-05"), "positive control")
+	l, _ := os.ReadFile(filepath.Join(b, "log.md"))
+	assert.Contains(t, string(l), "src")
+}