diff --git a/ingestion/cmd/server/main.go b/ingestion/cmd/server/main.go
index a91a961..f513463 100644
--- a/ingestion/cmd/server/main.go
+++ b/ingestion/cmd/server/main.go
@@ -16,6 +16,10 @@ import (
 
 	"github.com/mathiasbq/hyperguild/ingestion/internal/api"
 	"github.com/mathiasbq/hyperguild/ingestion/internal/claudewatcher"
+	"github.com/mathiasbq/hyperguild/ingestion/internal/audit"
+	"github.com/mathiasbq/hyperguild/ingestion/internal/capture"
+	"github.com/mathiasbq/hyperguild/ingestion/internal/capturehttp"
+	"github.com/mathiasbq/hyperguild/ingestion/internal/classification"
 	"github.com/mathiasbq/hyperguild/ingestion/internal/embed"
 	"github.com/mathiasbq/hyperguild/ingestion/internal/gitea"
 	"github.com/mathiasbq/hyperguild/ingestion/internal/graphstore"
@@ -119,6 +123,18 @@ func envInt(key string, fallback int) int {
 	return fallback
 }
 
+// splitList parses a comma-separated env value into a trimmed,
+// empty-free slice. Used for the capture sovereign-principal allowlist.
+func splitList(v string) []string {
+	var out []string
+	for _, p := range strings.Split(v, ",") {
+		if p = strings.TrimSpace(p); p != "" {
+			out = append(out, p)
+		}
+	}
+	return out
+}
+
 // systemHostname returns os.Hostname() with a "unknown" fallback so the
 // caller never has to handle the rare error path.
 func systemHostname() string {
@@ -349,6 +365,30 @@ func main() {
 
 	mux.Handle("/mcp", chassisauth.BearerMiddleware(mcpToken, jwtValidator, "brain", resourceMetadataURL, mcpSrv))
 
+	// POST /capture (#53): the uniform capture REST door. Needs a ticket
+	// tracker to file action items, so it only mounts when Gitea is
+	// configured. It reuses the MCP server's graph-wired brain store (one
+	// implementation), the classification tags for the I1 gate, and a slog
+	// audit sink (the loki+buffer sink lands in #54). The handler does its
+	// own auth (static + JWT) because it needs the principal to derive the
+	// trust-zone origin — the chassis middleware hides it.
+	if tracker := mcpSrv.IssueTracker(); tracker != nil {
+		classCfg, cerr := classification.Load(brainDir)
+		if cerr != nil {
+			logger.Error("load classification config", "err", cerr)
+			os.Exit(1)
+		}
+		captureSvc := capture.NewService(
+			mcpSrv.BrainStore(), tracker, nil, classCfg, audit.NewSlogSink(logger))
+		sovereign := splitList(os.Getenv("BRAIN_CAPTURE_SOVEREIGN_PRINCIPALS"))
+		captureH := capturehttp.New(captureSvc, jwtValidator, mcpToken, "local-cli",
+			capturehttp.NewOriginResolver(sovereign))
+		mux.Handle("POST /capture", captureH)
+		logger.Info("capture endpoint enabled", "sovereign_principals", len(sovereign))
+	} else {
+		logger.Info("capture endpoint disabled (BRAIN_GITEA_TOKEN unset)")
+	}
+
 	// Opt-in OAuth 2.0 client_credentials flow for claude.ai's custom-MCP
 	// integration UI, which has no static-Bearer field. Setting both
 	// OAUTH_CLIENT_ID and OAUTH_CLIENT_SECRET enables the token exchange;
diff --git a/ingestion/internal/capturehttp/handler.go b/ingestion/internal/capturehttp/handler.go
new file mode 100644
index 0000000..8bc73f0
--- /dev/null
+++ b/ingestion/internal/capturehttp/handler.go
@@ -0,0 +1,211 @@
+// Package capturehttp is the REST adapter for the capture use-case: the
+// POST /capture door (#53). It is deliberately thin — authenticate, derive
+// the trust-zone origin from the authenticated principal, decode the
+// request, call capture.Service, map the receipt to an HTTP status. No
+// business logic lives here; the I1 gate, validation, and orchestration
+// are all in the use-case.
+package capturehttp
+
+import (
+	"context"
+	"crypto/subtle"
+	"encoding/json"
+	"errors"
+	"net/http"
+	"strings"
+
+	"github.com/mathiasbq/hyperguild/ingestion/internal/capture"
+)
+
+// Validator validates a Bearer JWT and returns its subject. The chassis
+// *auth.JWTValidator satisfies it (including its nil-receiver "disabled"
+// behaviour), and tests can substitute a fake without a live JWKS.
+type Validator interface {
+	Validate(ctx context.Context, rawToken string) (string, error)
+}
+
+// Handler serves POST /capture.
+type Handler struct {
+	svc             *capture.Service
+	validator       Validator // nil ⇒ JWT auth disabled
+	staticToken     string    // "" ⇒ static auth disabled
+	staticPrincipal string    // principal name attributed to static-token callers
+	resolver        OriginResolver
+}
+
+// New constructs a capture HTTP handler. staticToken callers are
+// attributed to staticPrincipal (a sovereign homelab identity); JWT
+// callers are attributed to their token subject.
+func New(svc *capture.Service, validator Validator, staticToken, staticPrincipal string, resolver OriginResolver) *Handler {
+	if staticPrincipal == "" {
+		staticPrincipal = "local-cli"
+	}
+	return &Handler{
+		svc:             svc,
+		validator:       validator,
+		staticToken:     staticToken,
+		staticPrincipal: staticPrincipal,
+		resolver:        resolver,
+	}
+}
+
+// wire types — the POST /capture request body.
+type request struct {
+	Context  contextBody   `json:"context"`
+	Insights []insightBody `json:"insights"`
+	Tickets  []ticketBody  `json:"tickets"`
+	Summary  *summaryBody  `json:"summary,omitempty"`
+	DryRun   bool          `json:"dry_run"`
+}
+
+type contextBody struct {
+	Harness        string `json:"harness"`
+	SessionRef     string `json:"session_ref"`
+	Fidelity       string `json:"fidelity"`
+	Actor          string `json:"actor"`
+	Classification string `json:"classification"`
+}
+
+type insightBody struct {
+	Text          string `json:"text"`
+	Wing          string `json:"wing"`
+	Hall          string `json:"hall"`
+	SupersedeSlug string `json:"supersede_slug,omitempty"`
+}
+
+type ticketBody struct {
+	Repo   string `json:"repo"`
+	Action string `json:"action"`
+	Number int    `json:"number,omitempty"`
+	Title  string `json:"title,omitempty"`
+	Body   string `json:"body,omitempty"`
+}
+
+type summaryBody struct {
+	Title        string   `json:"title"`
+	Body         string   `json:"body"`
+	ReposTouched []string `json:"repos_touched,omitempty"`
+}
+
+// ServeHTTP authenticates, derives origin, runs the use-case, and maps the
+// result to an HTTP status.
+func (h *Handler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
+	principal, viaStatic, ok := h.authenticate(r)
+	if !ok {
+		http.Error(w, "unauthorized", http.StatusUnauthorized)
+		return
+	}
+
+	var req request
+	if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
+		writeJSON(w, http.StatusBadRequest, map[string]string{"error": "invalid JSON"})
+		return
+	}
+
+	in := req.toInput()
+	// Principal and origin are server-derived — overwrite anything the
+	// caller may have tried to put in the body.
+	in.Context.Principal = principal
+	in.Context.Origin = h.resolver.Resolve(principal, viaStatic)
+
+	rec, err := h.svc.Capture(r.Context(), in)
+	switch {
+	case errors.Is(err, capture.ErrSovereigntyRefused):
+		writeJSON(w, http.StatusForbidden, map[string]string{"error": err.Error()})
+		return
+	case err != nil:
+		// Pre-write validation failure (fail-closed).
+		writeJSON(w, http.StatusBadRequest, map[string]string{"error": err.Error()})
+		return
+	}
+	writeJSON(w, statusFor(rec), rec)
+}
+
+// authenticate mirrors the chassis Bearer precedence (static wins, then
+// JWT) but returns the resolved principal and whether the static path was
+// taken — the chassis middleware hides both, and capture needs them to
+// derive the origin.
+func (h *Handler) authenticate(r *http.Request) (principal string, viaStatic, ok bool) {
+	raw, found := strings.CutPrefix(r.Header.Get("Authorization"), "Bearer ")
+	if !found || raw == "" {
+		return "", false, false
+	}
+	if h.staticToken != "" && subtle.ConstantTimeCompare([]byte(raw), []byte(h.staticToken)) == 1 {
+		return h.staticPrincipal, true, true
+	}
+	if h.validator != nil {
+		if sub, err := h.validator.Validate(r.Context(), raw); err == nil && sub != "" {
+			return sub, false, true
+		}
+	}
+	return "", false, false
+}
+
+func (b request) toInput() capture.CaptureInput {
+	in := capture.CaptureInput{
+		Context: capture.CaptureContext{
+			Harness:        b.Context.Harness,
+			SessionRef:     b.Context.SessionRef,
+			Fidelity:       b.Context.Fidelity,
+			Actor:          b.Context.Actor,
+			Classification: b.Context.Classification,
+		},
+		DryRun: b.DryRun,
+	}
+	for _, i := range b.Insights {
+		in.Insights = append(in.Insights, capture.Insight{
+			Text: i.Text, Wing: i.Wing, Hall: i.Hall, SupersedeSlug: i.SupersedeSlug,
+		})
+	}
+	for _, t := range b.Tickets {
+		in.Tickets = append(in.Tickets, capture.Ticket{
+			Repo: t.Repo, Action: t.Action, Number: t.Number, Title: t.Title, Body: t.Body,
+		})
+	}
+	if b.Summary != nil {
+		in.Summary = &capture.Summary{
+			Title: b.Summary.Title, Body: b.Summary.Body, ReposTouched: b.Summary.ReposTouched,
+		}
+	}
+	return in
+}
+
+// statusFor maps a receipt to an HTTP status: 200 all-ok (or dry-run),
+// 207 partial, 502 everything-failed.
+func statusFor(rec capture.CaptureReceipt) int {
+	if rec.DryRun {
+		return http.StatusOK
+	}
+	var ok, fail int
+	for _, i := range rec.Insights {
+		count(&ok, &fail, i.OK)
+	}
+	for _, t := range rec.Tickets {
+		count(&ok, &fail, t.OK)
+	}
+	if rec.Summary != nil {
+		count(&ok, &fail, rec.Summary.OK)
+	}
+	switch {
+	case fail == 0:
+		return http.StatusOK
+	case ok == 0:
+		return http.StatusBadGateway // every persistence attempt failed
+	default:
+		return http.StatusMultiStatus // 207: partial success
+	}
+}
+
+func count(ok, fail *int, isOK bool) {
+	if isOK {
+		*ok++
+	} else {
+		*fail++
+	}
+}
+
+func writeJSON(w http.ResponseWriter, status int, v any) {
+	w.Header().Set("Content-Type", "application/json")
+	w.WriteHeader(status)
+	_ = json.NewEncoder(w).Encode(v)
+}
diff --git a/ingestion/internal/capturehttp/handler_test.go b/ingestion/internal/capturehttp/handler_test.go
new file mode 100644
index 0000000..a2247cc
--- /dev/null
+++ b/ingestion/internal/capturehttp/handler_test.go
@@ -0,0 +1,178 @@
+package capturehttp_test
+
+import (
+	"bytes"
+	"context"
+	"encoding/json"
+	"errors"
+	"net/http"
+	"net/http/httptest"
+	"testing"
+
+	"github.com/mathiasbq/hyperguild/ingestion/internal/audit"
+	"github.com/mathiasbq/hyperguild/ingestion/internal/brainstore"
+	"github.com/mathiasbq/hyperguild/ingestion/internal/capture"
+	"github.com/mathiasbq/hyperguild/ingestion/internal/capturehttp"
+	"github.com/mathiasbq/hyperguild/ingestion/internal/classification"
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+const staticTok = "static-secret"
+
+// fakeValidator stands in for the chassis JWT validator.
+type fakeValidator struct {
+	subject string
+	err     error
+}
+
+func (f fakeValidator) Validate(context.Context, string) (string, error) {
+	return f.subject, f.err
+}
+
+type fakeTracker struct{ failCreate bool }
+
+func (f fakeTracker) CreateIssue(context.Context, string, string, string) (capture.IssueRef, error) {
+	if f.failCreate {
+		return capture.IssueRef{}, errors.New("gitea down")
+	}
+	return capture.IssueRef{Repo: "hyperguild", Number: 1, URL: "https://git/1"}, nil
+}
+func (fakeTracker) CloseIssue(context.Context, string, int, string) (capture.IssueRef, error) {
+	return capture.IssueRef{}, nil
+}
+func (fakeTracker) CommentIssue(context.Context, string, int, string) (capture.IssueRef, error) {
+	return capture.IssueRef{}, nil
+}
+
+func newHandler(t *testing.T, v capturehttp.Validator, tr capture.IssueTracker, sovereign []string) *capturehttp.Handler {
+	t.Helper()
+	cfg, err := classification.Load(t.TempDir())
+	require.NoError(t, err)
+	svc := capture.NewService(brainstore.New(t.TempDir()), tr, nil, cfg, audit.NewSlogSink(nil))
+	return capturehttp.New(svc, v, staticTok, "local-cli", capturehttp.NewOriginResolver(sovereign))
+}
+
+func do(t *testing.T, h *capturehttp.Handler, authz string, body any) *httptest.ResponseRecorder {
+	t.Helper()
+	b, _ := json.Marshal(body)
+	req := httptest.NewRequest(http.MethodPost, "/capture", bytes.NewReader(b))
+	if authz != "" {
+		req.Header.Set("Authorization", authz)
+	}
+	rr := httptest.NewRecorder()
+	h.ServeHTTP(rr, req)
+	return rr
+}
+
+func internalReq() map[string]any {
+	return map[string]any{
+		"context":  map[string]any{"harness": "claude-code", "actor": "mathias", "classification": "internal"},
+		"insights": []map[string]any{{"text": "a fact", "wing": "hyperguild", "hall": "facts"}},
+	}
+}
+
+func TestUnauthorizedWithoutToken(t *testing.T) {
+	h := newHandler(t, fakeValidator{err: errors.New("no")}, fakeTracker{}, nil)
+	rr := do(t, h, "", internalReq())
+	assert.Equal(t, http.StatusUnauthorized, rr.Code)
+}
+
+func TestUnauthorizedBadToken(t *testing.T) {
+	h := newHandler(t, fakeValidator{err: errors.New("bad jwt")}, fakeTracker{}, nil)
+	rr := do(t, h, "Bearer wrong", internalReq())
+	assert.Equal(t, http.StatusUnauthorized, rr.Code)
+}
+
+func TestHappyPathStaticToken(t *testing.T) {
+	h := newHandler(t, nil, fakeTracker{}, nil)
+	rr := do(t, h, "Bearer "+staticTok, map[string]any{
+		"context":  map[string]any{"harness": "claude-code", "actor": "mathias", "classification": "internal"},
+		"insights": []map[string]any{{"text": "a fact", "wing": "hyperguild", "hall": "facts"}},
+		"tickets":  []map[string]any{{"repo": "hyperguild", "action": "create", "title": "t"}},
+	})
+	require.Equal(t, http.StatusOK, rr.Code)
+	var rec capture.CaptureReceipt
+	require.NoError(t, json.Unmarshal(rr.Body.Bytes(), &rec))
+	assert.True(t, rec.Insights[0].OK)
+	assert.True(t, rec.Tickets[0].OK)
+	assert.Empty(t, rec.Errors)
+}
+
+func TestConfidentialViaUSNexusRefused(t *testing.T) {
+	// JWT principal not in the sovereign allowlist ⇒ us-nexus; confidential ⇒ 403.
+	h := newHandler(t, fakeValidator{subject: "claudeai-oauth-client"}, fakeTracker{}, nil)
+	rr := do(t, h, "Bearer jwt-token", map[string]any{
+		"context":  map[string]any{"harness": "claudeai-chat", "actor": "mathias", "classification": "confidential"},
+		"insights": []map[string]any{{"text": "secret", "wing": "client-seb", "hall": "facts"}},
+	})
+	assert.Equal(t, http.StatusForbidden, rr.Code)
+	assert.Contains(t, rr.Body.String(), "sovereignty")
+}
+
+func TestConfidentialViaSovereignJWTAllowed(t *testing.T) {
+	// Same confidential payload, but the principal is allowlisted sovereign ⇒ allowed.
+	h := newHandler(t, fakeValidator{subject: "koala-cli"}, fakeTracker{}, []string{"koala-cli"})
+	rr := do(t, h, "Bearer jwt-token", map[string]any{
+		"context":  map[string]any{"harness": "claude-code", "actor": "mathias", "classification": "confidential"},
+		"insights": []map[string]any{{"text": "secret", "wing": "client-seb", "hall": "facts"}},
+	})
+	require.Equal(t, http.StatusOK, rr.Code)
+}
+
+func TestStaticTokenIsSovereignSoConfidentialAllowed(t *testing.T) {
+	h := newHandler(t, nil, fakeTracker{}, nil)
+	rr := do(t, h, "Bearer "+staticTok, map[string]any{
+		"context":  map[string]any{"harness": "claude-code", "actor": "mathias", "classification": "confidential"},
+		"insights": []map[string]any{{"text": "secret", "wing": "client-seb", "hall": "facts"}},
+	})
+	assert.Equal(t, http.StatusOK, rr.Code)
+}
+
+func TestValidationRejectedBeforeWrite(t *testing.T) {
+	h := newHandler(t, nil, fakeTracker{}, nil)
+	rr := do(t, h, "Bearer "+staticTok, map[string]any{
+		"context":  map[string]any{"actor": "mathias", "classification": "internal"},
+		"insights": []map[string]any{{"text": "x", "wing": "hyperguild", "hall": "not-a-hall"}},
+	})
+	assert.Equal(t, http.StatusBadRequest, rr.Code)
+}
+
+func TestPartialFailureIs207(t *testing.T) {
+	h := newHandler(t, nil, fakeTracker{failCreate: true}, nil)
+	rr := do(t, h, "Bearer "+staticTok, map[string]any{
+		"context":  map[string]any{"harness": "claude-code", "actor": "mathias", "classification": "internal"},
+		"insights": []map[string]any{{"text": "ok insight", "wing": "hyperguild", "hall": "facts"}},
+		"tickets":  []map[string]any{{"repo": "hyperguild", "action": "create", "title": "fails"}},
+	})
+	assert.Equal(t, http.StatusMultiStatus, rr.Code)
+	var rec capture.CaptureReceipt
+	require.NoError(t, json.Unmarshal(rr.Body.Bytes(), &rec))
+	assert.True(t, rec.Insights[0].OK)
+	assert.False(t, rec.Tickets[0].OK)
+	assert.Len(t, rec.Errors, 1)
+}
+
+func TestDryRunWritesNothing(t *testing.T) {
+	h := newHandler(t, nil, fakeTracker{}, nil)
+	rr := do(t, h, "Bearer "+staticTok, map[string]any{
+		"context":  map[string]any{"harness": "claude-code", "actor": "mathias", "classification": "internal"},
+		"insights": []map[string]any{{"text": "a", "wing": "hyperguild", "hall": "facts"}},
+		"dry_run":  true,
+	})
+	require.Equal(t, http.StatusOK, rr.Code)
+	var rec capture.CaptureReceipt
+	require.NoError(t, json.Unmarshal(rr.Body.Bytes(), &rec))
+	assert.True(t, rec.DryRun)
+}
+
+func TestCallerCannotForgeOrigin(t *testing.T) {
+	// Even if the body tried to assert a sovereign harness, a us-nexus JWT
+	// principal + confidential ⇒ refused. (Origin is server-derived.)
+	h := newHandler(t, fakeValidator{subject: "claudeai-oauth-client"}, fakeTracker{}, nil)
+	rr := do(t, h, "Bearer jwt", map[string]any{
+		"context":  map[string]any{"harness": "sovereign-soil", "actor": "mathias", "classification": "confidential"},
+		"insights": []map[string]any{{"text": "secret", "wing": "client-seb", "hall": "facts"}},
+	})
+	assert.Equal(t, http.StatusForbidden, rr.Code)
+}
diff --git a/ingestion/internal/capturehttp/origin.go b/ingestion/internal/capturehttp/origin.go
new file mode 100644
index 0000000..b449371
--- /dev/null
+++ b/ingestion/internal/capturehttp/origin.go
@@ -0,0 +1,42 @@
+package capturehttp
+
+import "github.com/mathiasbq/hyperguild/ingestion/internal/capture"
+
+// OriginResolver maps an authenticated principal to its trust zone
+// (spec §4.2). The mapping is server-side and never reads caller input.
+//
+// Rules:
+//   - The static-token path is a homelab CLI caller on sovereign soil →
+//     ZoneSovereign.
+//   - A JWT principal in the sovereign allowlist → ZoneSovereign.
+//   - Any other JWT principal (e.g. claude.ai's OAuth identity, or any
+//     unrecognised subject) → ZoneUSNexus.
+//
+// The default is the strict one: an unknown principal is treated as
+// us-nexus so the I1 gate fails safe (refuses confidential), exactly as
+// an untagged classification target fails safe to confidential (#50).
+type OriginResolver struct {
+	sovereign map[string]bool
+}
+
+// NewOriginResolver builds a resolver whose JWT sovereign principals are
+// the given subjects. The static-token caller is always sovereign and
+// need not be listed.
+func NewOriginResolver(sovereignPrincipals []string) OriginResolver {
+	m := make(map[string]bool, len(sovereignPrincipals))
+	for _, p := range sovereignPrincipals {
+		if p != "" {
+			m[p] = true
+		}
+	}
+	return OriginResolver{sovereign: m}
+}
+
+// Resolve returns the trust zone for a principal. viaStatic is true when
+// the static-token auth path was taken.
+func (r OriginResolver) Resolve(principal string, viaStatic bool) capture.Zone {
+	if viaStatic || r.sovereign[principal] {
+		return capture.ZoneSovereign
+	}
+	return capture.ZoneUSNexus
+}
diff --git a/ingestion/internal/mcp/server.go b/ingestion/internal/mcp/server.go
index a88a21b..84d94d5 100644
--- a/ingestion/internal/mcp/server.go
+++ b/ingestion/internal/mcp/server.go
@@ -116,6 +116,13 @@ func (s *Server) IssueTracker() capture.IssueTracker {
 	return s.tracker
 }
 
+// BrainStore returns the shared brain store (graph-wired once WithGraph
+// has run), so the capture use-case writes through the exact same
+// implementation as the MCP handlers.
+func (s *Server) BrainStore() *brainstore.Store {
+	return s.store
+}
+
 func (s *Server) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 	// MCP streamable HTTP: GET establishes the SSE stream for server-to-client events.
 	if r.Method == http.MethodGet {