Four call sites did `s[:limit] + "…"`. Both halves are byte operations: len() counts bytes and a slice cuts bytes. On Swedish text — å ä ö are two bytes, an em dash three — the cut lands mid-character and leaves an orphaned lead byte, producing invalid UTF-8. It failed loudly in exactly one place: wiki/index.md is written raw to disk, where every strict decoder then rejects the whole file. The other three (brain_context excerpts x2, brain_query excerpts) feed MCP responses, where encoding/json silently substitutes U+FFFD — so those had been quietly eating the last character of truncated excerpts, with no error anywhere and nothing to notice. textutil.Truncate counts runes and appends the marker only when content was actually dropped; an ellipsis on complete text is a lie about the content. The test is a property, not an example: it walks the limit across every offset of a multi-byte string and asserts utf8.Valid at each one, so a future off-by-one cannot pass by picking a lucky boundary. Co-Authored-By: Claude Opus 5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01BeAp5LTscnz2W7Ubt4eJ6m
hyperguild
An MCP server that acts as a disciplined AI supervisor for Claude Code sessions. Instead of letting Claude Code do whatever it wants, hyperguild enforces structured workflows (TDD red/green/refactor), logs every session, and accumulates learnings into a searchable brain.
Hypothesis
We believe routing skill tasks through local models, backed by brain context, produces measurably better outcomes than raw Claude Code alone — measurable by per-skill pass rate over rolling 30-day windows (available at
GET /pass-rate?skill=<name>&window=30don the brain pod).
This is the falsifiable claim the routing pod and pass-rate infrastructure exist to test. If per-skill pass rates don't improve over baseline (all-cloud) after 30 days of real usage, the fast-model routing path should be reconsidered.
Harness
hyperguild = Claude Code + MCP. This is a supervisor for Claude Code sessions specifically. For multi-agent orchestration (OpenCode + LiteLLM, executor/reviewer pipelines), see agentsquad — a separate harness for a different orchestration model. Skills (mathias/skills) are shared between both.
How it works
Your Claude Code session (in any project)
│
│ MCP over HTTP (Tailscale)
├──▶ routing :3210 (NodePort 30310 on koala) — review, debug, retrospective, trainer
└──▶ brain :3300 (NodePort 30330 on koala) — brain_query, brain_write, brain_ingest, session_log
│
└─ also serves the legacy REST endpoints (/query, /write, /ingest, …)
│
▼
brain/
├── sessions/ — JSONL log, one file per session_id
├── wiki/ — searchable knowledge (wing/hall layout)
│ ├── homelab/
│ ├── claude-sessions/
│ └── ...
└── knowledge/ — legacy flat notes (migration pending: hyperguild#22)
Phase 1 tools (available now)
| Tool | What it does |
|---|---|
session_log |
Appends a structured entry to the session JSONL log |
retrospective |
Reads the session log, identifies novel learnings, writes to brain |
review |
Structured code review via local model, brain-context injected |
debug |
Hypothesis-driven debugging via local model |
brain_query |
Full-text search over brain/wiki/ |
brain_write |
Writes a note to brain (with wing/hall routing) |
brain_answer |
BM25 + LLM synthesis — Q&A over brain corpus |
tier |
Returns the current connectivity tier (1=cloud, 2=LAN, 3=offline) |
Note:
tdd_red/green/refactorandspecwere retired in Plan 7 (2026-05-12). They are now SKILL.md files in mathias/skills.
Connect a project
Create .mcp.json in your project root:
{
"mcpServers": {
"routing": {
"type": "http",
"url": "http://koala:30310/mcp"
},
"brain": {
"type": "http",
"url": "http://koala:30330/mcp"
}
}
}
Two MCP servers are exposed, both reachable over Tailscale:
routingatkoala:30310— skill workers (review,debug,retrospective,trainer). Routes each call to fast local model or thinking model based on per-skill pass rate.brainatkoala:30330— knowledge access (brain_query,brain_write,brain_ingest,brain_ingest_raw,brain_answer,brain_classify) andsession_log.
No local binary or stdio shim is required — Claude Code talks to both via HTTP.
Open Claude Code in your project — run /mcp to confirm both servers are listed.
A typical session
1. Call review → brain context injected + local model review → findings
2. Call session_log → log each phase result
3. Call retrospective → extracts learnings → brain
4. Future sessions: call brain_query / brain_answer to retrieve relevant context
Tier detection
The routing pod probes connectivity at call time:
| Tier | Label | Condition |
|---|---|---|
| 1 | full-online | Can reach api.anthropic.com |
| 2 | lan-only | Can reach LiteLLM but not Anthropic |
| 3 | airplane | No external connectivity |
Model routing
The routing pod selects models per skill call based on historical pass rate:
| Pass rate | Decision |
|---|---|
| ≥ 0.90 (FLOOR) | Fast model (HYPERGUILD_FAST_MODEL) |
| ≤ 0.70 (CEIL) | Thinking model (HYPERGUILD_THINKING_MODEL) |
| between CEIL and FLOOR | Sample band — probabilistic routing |
| nil (no history yet) | Defaults to thinking model |
Bootstrap note: With no session history, all calls route to the thinking model. The fast-model path activates only after real pass-rate data accumulates at
/pass-rate. Seed with real usage — don't try to pre-populate.
Key env vars
| Variable | Default | Purpose |
|---|---|---|
INGEST_BRAIN_DIR |
../brain |
Brain directory for ingestion server |
INGEST_PORT |
3300 |
Ingestion server port |
INGEST_BASE_URL |
http://localhost:3300 |
Routing pod → brain |
LITELLM_BASE_URL |
— | LiteLLM proxy for Tier 2 model routing |
ROUTING_PORT |
3210 |
Routing pod's listen port |
ROUTING_MCP_TOKEN |
— | Optional bearer token; when empty, no auth enforced |
BRAIN_URL |
http://ingestion.supervisor:3300 |
Routing pod → brain (in-cluster) |
HYPERGUILD_FAST_MODEL |
koala/qwen35-9b-fast |
Fast model for high-pass-rate skill calls |
HYPERGUILD_THINKING_MODEL |
iguana/gemma4-26b |
Thinking model for low-pass-rate skill calls |
HYPERGUILD_ROUTE_LOCAL_FLOOR |
0.90 |
Fast model threshold |
HYPERGUILD_ROUTE_LOCAL_CEIL |
0.70 |
Thinking model threshold |
HYPERGUILD_PASS_RATE_TTL_SECONDS |
60 |
Per-skill pass-rate cache TTL |
Operator note: LiteLLM at
LITELLM_BASE_URLmust register bothHYPERGUILD_FAST_MODELandHYPERGUILD_THINKING_MODEL. If a model is missing, the fail-open retry also fails and the only signal isfinal_status: "fail"on_routingentries in the brain.
Open issues
See issues — key open items:
- #25 — skills platform overhaul (audit first, then lazy loading + brain feedback loop)
- #24 — reduce context burn from skill listing
- #22 — migrate legacy brain notes to wing/hall layout (one-shot script, low risk)
- #31 — connect routing-mcp to claude.ai as custom connector