feat: OpenAPI and MCP from the same serve handlers (#20)

Agents get GET /openapi.json and POST /mcp. Tool names match
search/get/stats/audit paths so PicoClaw does not need shebangs.

AGENTS.md

@@ -77,12 +77,15 @@ bin/brain/index.go --rebuild                                            # rebuil
 ## Tools
 
 ```bash
-bin/facts/audit ["self"|"facts"|"info"|"stale"]   # 2-source + staleness gate
-bin/facts/crm [--dry-run]                         # proof person↔company/company↔project (ooCRM × corpus SoT)
+bin/facts/audit.go ["self"|"facts"|"info"|"stale"]  # 2-source + staleness gate
+bin/facts/crm.go [--dry-run]                       # proof person↔company/company↔project (ooCRM × corpus SoT)
 bin/kb/search "query" [--repo X]                  # deprecated wrapper → bin/brain/search.go
 bin/brain/search.go "query" [--root facts|info]   # deduction search → YAML
 bin/brain/search.go "query" --no-web              # local graph only
-bin/brain/get.go <id> [--body]
+bin/brain/get.go <id> [--body] [--json]          # Go read; Python bin/kb/get CI fallback
+bin/brain/stats.go [--json]
+bin/brain/eval.go [--json]                       # recall@5; questions in internal/brain/rank
+bin/brain/serve.go                               # HTTP :8630; GET /openapi.json POST /mcp
 bin/markdown/import.go [dir]                      # mistune leaves → YAML
 bin/git/import.go [REPO] [--json] [--limit N]     # go-git history → commit leafs
 bin/web/search.go "query" [--json]                # SearXNG; throttled ≠ absence

PLAN.md

@@ -29,7 +29,7 @@ detective method: **a fact needs ≥2 independent sources or it is
 | D3 | web search | Go client `bin/web/search.go` (`internal/websearch`). SearXNG URL is config (`BRAIN_SEARCH_URL`). Optional Compose profile `searxng` (sanitized settings). Do not run a second copy on a host that already has one. Empty/`throttled` ≠ “nothing exists”. |
 | D4 | embeddings | **model2vec** `minishlab/potion-multilingual-128M` instead of embeddinggemma. |
 | D5 | parser | **mistune** for MD → leaf extraction (duckdb-md documented as future optional SQL/export layer, not v1). |
-| D6 | graph engine | **LadybugDB**. Go is the service (`bin/brain/search.go`, `bin/brain/serve.go` in-process, `internal/brain`); Python remains for index/write until the Go write path is safe. |
+| D6 | graph engine | **LadybugDB**. Go is the service (`bin/brain/search.go`, `bin/brain/serve.go` in-process, `internal/brain`). Read path (`get.go` / `stats.go` / `eval.go`) is Go + cgo. Python `bin/kb/{get,stats,eval}` is the CI fallback (GitHub runners have no ladybug cgo). Index/write stays Python until the Go write path is safe. |
 | D7 | db access | `db-yaml`/`psql-yq`-style, read-only, YAML out. OnlyOffice Postgres via SSH tunnel (`127.0.0.1:5433`). |
 | D8 | evidence | detective method: ≥2 independent sources or `(not confirmed)`. Auto-pair docker ps × compose × ssh-config × docs. |
 | D9 | facts/goal model | Who / What / How / Where / When + evidence + confidence on every edge. |
@@ -43,6 +43,7 @@ detective method: **a fact needs ≥2 independent sources or it is
 | D17 | assertion gate | Fact-check every *claim* (facts → info → live → web), not every edit. `bin/brain/search.go` adds a `web` block when there is no facts hit (`throttled`/`skipped`/`refused` ≠ absence). `--root` and `--no-web` stay local. Missing graph ≠ “does not exist”. |
 | D18 | reasoner | Pluggable OpenAI-compatible URL. RAM: Qwen3.5-9B. Quality: Bonsai-27B or Qwen3.6-27B. No official Qwen3.6-9B. |
 | D19 | git history | [go-git](https://github.com/go-git/go-git) via `bin/git/import.go`. No subprocess of the git binary. Conversion prints commit leafs; brain write is `bin/brain/index.go`. |
+| D20 | agent API | OpenAPI + MCP are generated from the same `internal/httpapi.Ops` table as `bin/brain/serve.go` handlers. `GET /openapi.json`, `POST /mcp` (JSON-RPC tools/list + tools/call). Tool names match OpenAPI paths (`search`/`get`/`stats`/`audit`). |
 
 ## Architecture
 
@@ -52,13 +53,13 @@ detective method: **a fact needs ≥2 independent sources or it is
   docs/                     published docs (this conversation → docs/ as md)
   skills/                   in-project skills (web-search, db-yaml, brain, diataxis-docs)
   bin/
-    facts/extract           auto-pair 2 sources → lexicon yaml + graph
-    facts/audit             ["self"|"facts"|"info"|"stale"] 2-source + staleness gate
+    facts/extract.go audit.go crm.go  # D14 shebang; Python implementation
     kb/index                Python write path (called by bin/brain/index.go)
     brain/index.go          rebuild FTS + HNSW (incl. --with-mail)
-    brain/get.go stats.go eval.go watch.go
+    brain/get.go stats.go eval.go  # Go read (cgo); Python bin/kb/* CI fallback
+    brain/watch.go
     brain/search.go         deduction: facts → info → web-search
-    brain/serve.go          HTTP API in-process (internal/httpapi + internal/brain)
+    brain/serve.go          HTTP API in-process + OpenAPI/MCP (D20)
     mail/import.go          JSON → markdown (no brain write)
     markdown/import.go      mistune leaves
     postgres/query.go       read-only YAML (wraps bin/db/psql-yq)
@@ -132,8 +133,10 @@ Common props on every node/edge: `root`, `confidence`, `evidence[]`, `how`,
 1. go vet + go test ./... (root module; packages without ladybug cgo)
 2. `go test ./internal/brain/rank` (cgo-free ranking + flag parser)
 3. python -m unittest discover -s bin/tools (includes published-docs SoT)
-4. bin/facts/audit self  (lexicon internal consistency)
-5. bin/brain/eval.go       (recall@5 ≥ 0.95, gates index regressions)
+4. `bin/facts/audit self` (lexicon internal consistency; `bin/facts/audit.go` is the D14 wrapper)
+5. `bin/kb/eval` (recall@5 ≥ 0.95). Local SoT is `bin/brain/eval.go`; CI uses
+   the Python twin until the runner has ladybug cgo. Questions live in
+   `internal/brain/rank`.
 6. md-docs build/lint if docs tooling arrives.
 
 Feedback loop: every commit → PR → CI → green/gate → merge. Same discipline as

README.md

@@ -28,8 +28,8 @@ graph TB
     end
 
     subgraph dph["2dph tools"]
-        EX["bin/facts/extract<br/>2-source pairing"]
-        AU["bin/facts/audit<br/>confidence + staleness"]
+        EX["bin/facts/extract.go<br/>2-source pairing"]
+        AU["bin/facts/audit.go<br/>confidence + staleness"]
         IDX["bin/brain/index.go<br/>chunk + embed"]
         MD["bin/markdown/import.go<br/>mistune leaves"]
         SR["bin/brain/search.go<br/>deduction"]
@@ -126,7 +126,8 @@ bin/brain/search.go "invoice from last week"                            # same s
 
 - **LadybugDB** — single `var/kb.lbug`, Cypher property graph, HNSW + BM25
   in one engine, embedded (no server), ACID, read-only-safe for concurrent
-  readers. **Never `DROP INDEX` FTS/VECTOR** on Ladybug 0.19: DROP leaves
+  readers. Read tools (`get` / `stats` / `eval`) are Go + cgo; Python
+  `bin/kb/{get,stats,eval}` is the CI fallback. **Never `DROP INDEX` FTS/VECTOR** on Ladybug 0.19: DROP leaves
   ghost catalog tables (`_0_Leaf_vec_UPPER`) so recreate fails while
   `SHOW_INDEXES` omits HNSW. Fresh indexes = delete `var/kb.lbug` +
   `bin/brain/index.go --rebuild`. Use `ensure_indexes()` after upserts.
@@ -140,14 +141,14 @@ bin/brain/search.go "invoice from last week"                            # same s
 `bin/{subject}/{method}.go` — self-describing: shebang on line 1, usage comment
 from line 2. Shared code in `internal/`. YAML default output, `--json` for
 machines. Tests gate every commit. HTTP: `bin/brain/serve.go` calls
-`internal/brain` in-process (`/health` `/search` `/get` `/stats` `/audit` `/ingest`).
+`internal/brain` in-process (`/health` `/search` `/get` `/stats` `/audit` `/ingest` `/openapi.json` `/mcp`).
 
 ## Development
 
 ```bash
 uv venv .venv                                  # Python 3.12, uv-managed
 uv pip install -r requirements.lock.txt        # pinned toolchain
-bin/facts/audit self                           # lexicon consistency gate
+bin/facts/audit.go self                        # lexicon consistency gate
 go test ./... && python -m unittest discover -s bin/tools -t .
 ```
 

bin/brain/eval.go

@@ -1,20 +1,22 @@
-//usr/bin/env go run -tags=brain_eval "$0" "$@"; exit
-//go:build brain_eval
+//usr/bin/env go run -tags=system_ladybug,brain_eval "$0" "$@"; exit
+//go:build cgo && system_ladybug && brain_eval
 //
 // bin/brain/eval.go - recall@5 gate.
 //
 //	./bin/brain/eval.go
 //	./bin/brain/eval.go --json
 //
+// Needs CGO + libladybug. Python bin/kb/eval is the CI fallback (no cgo).
+// Control questions live in internal/brain/rank (cgo-free).
 // NOTE: never run `gofmt -w` on this file — it breaks the shebang.
 package main
 
 import (
 	"os"
 
-	"github.com/eSlider/2dph/internal/cmdbin"
+	"github.com/eSlider/2dph/internal/brain"
 )
 
 func main() {
-	os.Exit(cmdbin.ExecFile("bin/kb/eval", os.Args[1:]))
+	os.Exit(brain.MainEval(os.Args[1:]))
 }

bin/brain/get.go

@@ -1,20 +1,22 @@
-//usr/bin/env go run -tags=brain_get "$0" "$@"; exit
-//go:build brain_get
+//usr/bin/env go run -tags=system_ladybug,brain_get "$0" "$@"; exit
+//go:build cgo && system_ladybug && brain_get
 //
 // bin/brain/get.go - read one leaf by id.
 //
 //	./bin/brain/get.go <id>
 //	./bin/brain/get.go <id> --body
+//	./bin/brain/get.go <id> --json
 //
+// Needs CGO + libladybug. Python bin/kb/get is the CI fallback (no cgo).
 // NOTE: never run `gofmt -w` on this file — it breaks the shebang.
 package main
 
 import (
 	"os"
 
-	"github.com/eSlider/2dph/internal/cmdbin"
+	"github.com/eSlider/2dph/internal/brain"
 )
 
 func main() {
-	os.Exit(cmdbin.ExecFile("bin/kb/get", os.Args[1:]))
+	os.Exit(brain.MainGet(os.Args[1:]))
 }

bin/brain/serve.go

@@ -6,6 +6,9 @@
 //	KB_ROOT=/path/to/2dph ./bin/brain/serve.go
 //	KB_WORKERS=4 KB_PORT=8630 ./bin/brain/serve.go
 //
+//	GET  /openapi.json  same Ops table as the handlers
+//	POST /mcp           JSON-RPC tools/list + tools/call
+//
 // Needs CGO + libladybug (same as bin/brain/search.go).
 // NOTE: never run `gofmt -w` on this file — it breaks the shebang.
 package main

bin/brain/stats.go

@@ -1,20 +1,21 @@
-//usr/bin/env go run -tags=brain_stats "$0" "$@"; exit
-//go:build brain_stats
+//usr/bin/env go run -tags=system_ladybug,brain_stats "$0" "$@"; exit
+//go:build cgo && system_ladybug && brain_stats
 //
 // bin/brain/stats.go - index health.
 //
 //	./bin/brain/stats.go
 //	./bin/brain/stats.go --json
 //
+// Needs CGO + libladybug. Python bin/kb/stats is the CI fallback (no cgo).
 // NOTE: never run `gofmt -w` on this file — it breaks the shebang.
 package main
 
 import (
 	"os"
 
-	"github.com/eSlider/2dph/internal/cmdbin"
+	"github.com/eSlider/2dph/internal/brain"
 )
 
 func main() {
-	os.Exit(cmdbin.ExecFile("bin/kb/stats", os.Args[1:]))
+	os.Exit(brain.MainStats(os.Args[1:]))
 }

bin/facts/audit.go

@@ -0,0 +1,21 @@
+//usr/bin/env go run -tags=facts_audit "$0" "$@"; exit
+//go:build facts_audit
+//
+// bin/facts/audit.go - 2-source + lexicon checks.
+//
+//	./bin/facts/audit.go self
+//	./bin/facts/audit.go db
+//
+// Python bin/facts/audit is the implementation (CI runs it directly).
+// NOTE: never run `gofmt -w` on this file — it breaks the shebang.
+package main
+
+import (
+	"os"
+
+	"github.com/eSlider/2dph/internal/cmdbin"
+)
+
+func main() {
+	os.Exit(cmdbin.ExecFile("bin/facts/audit", os.Args[1:]))
+}

bin/facts/crm.go

@@ -0,0 +1,20 @@
+//usr/bin/env go run -tags=facts_crm "$0" "$@"; exit
+//go:build facts_crm
+//
+// bin/facts/crm.go - prove person↔company / company↔project (ooCRM × corpus).
+//
+//	./bin/facts/crm.go [--dry-run] [--mismatches]
+//
+// Python bin/facts/crm is the implementation. Graph write stays Python.
+// NOTE: never run `gofmt -w` on this file — it breaks the shebang.
+package main
+
+import (
+	"os"
+
+	"github.com/eSlider/2dph/internal/cmdbin"
+)
+
+func main() {
+	os.Exit(cmdbin.ExecFile("bin/facts/crm", os.Args[1:]))
+}

bin/facts/extract.go

@@ -0,0 +1,20 @@
+//usr/bin/env go run -tags=facts_extract "$0" "$@"; exit
+//go:build facts_extract
+//
+// bin/facts/extract.go - acquire confirmed facts (2-source each).
+//
+//	./bin/facts/extract.go [--json] [--dry-run]
+//
+// Python bin/facts/extract is the implementation. Graph write stays Python.
+// NOTE: never run `gofmt -w` on this file — it breaks the shebang.
+package main
+
+import (
+	"os"
+
+	"github.com/eSlider/2dph/internal/cmdbin"
+)
+
+func main() {
+	os.Exit(cmdbin.ExecFile("bin/facts/extract", os.Args[1:]))
+}

bin/tools/test_bin_layout.py

@@ -77,6 +77,44 @@ class BinLayoutTest(unittest.TestCase):
         for method in ("index.go", "get.go", "stats.go", "eval.go", "watch.go"):
             self._assert_shebang(f"bin/brain/{method}")
 
+    def test_brain_get_stats_eval_are_not_python_exec(self) -> None:
+        for method in ("get.go", "stats.go", "eval.go"):
+            text = (ROOT / "bin" / "brain" / method).read_text()
+            self.assertNotIn(
+                "ExecFile",
+                text,
+                f"bin/brain/{method} must call internal/brain, not ExecFile Python",
+            )
+            self.assertNotIn(
+                "cmdbin",
+                text,
+                f"bin/brain/{method} must not import internal/cmdbin",
+            )
+            self.assertIn(
+                "system_ladybug",
+                text.splitlines()[0],
+                f"bin/brain/{method} shebang must pass -tags=system_ladybug",
+            )
+            self.assertIn(
+                "github.com/eSlider/2dph/internal/brain",
+                text,
+            )
+
+    def test_eval_control_questions_live_in_rank(self) -> None:
+        rank = (ROOT / "internal" / "brain" / "rank" / "evalq.go").read_text()
+        py = (ROOT / "bin" / "kb" / "eval").read_text()
+        for frag in ("BM25", "DevOps", "LadybugDB"):
+            self.assertIn(frag, rank)
+            self.assertIn(frag, py)
+        self.assertIn("0.95", rank)
+
+    def test_facts_methods_are_shebangs(self) -> None:
+        for method in ("audit.go", "extract.go", "crm.go"):
+            self._assert_shebang(f"bin/facts/{method}")
+            text = (ROOT / "bin" / "facts" / method).read_text()
+            self.assertIn("cmdbin.ExecFile", text)
+            self.assertIn(f"bin/facts/{method.removesuffix('.go')}", text)
+
     def test_mail_import_is_shebang_not_brain_write(self) -> None:
         self._assert_shebang("bin/mail/import.go")
         index_mail = (ROOT / "bin" / "mail" / "index_mail").read_text()

bin/tools/test_published_docs.py

@@ -59,6 +59,22 @@ class PublishedDocsTest(unittest.TestCase):
         self.assertNotIn("password", settings.lower())
         self.assertIn("json", settings)
 
+    def test_readme_read_path_is_go(self) -> None:
+        plan = (ROOT / "PLAN.md").read_text()
+        self.assertIn("get.go", plan)
+        self.assertIn("CI fallback", plan)
+        design = (ROOT / "docs" / "design.md").read_text()
+        self.assertIn("internal/brain/rank", design)
+        self.assertIn("They do not exec Python", design)
+
+    def test_openapi_mcp_from_same_handlers(self) -> None:
+        plan = (ROOT / "PLAN.md").read_text()
+        self.assertIn("D20", plan)
+        self.assertIn("/openapi.json", (ROOT / "README.md").read_text())
+        self.assertIn("/mcp", (ROOT / "README.md").read_text())
+        skill = (ROOT / "skills" / "brain" / "SKILL.md").read_text()
+        self.assertIn("/mcp", skill)
+
     def test_readme_search_escalates_web(self) -> None:
         text = (ROOT / "README.md").read_text()
         self.assertIn("--no-web", text)

docs/crm-associations-proof.md

@@ -1,33 +0,0 @@
-# CRM association proof (oo CLI ↔ corpus)
-
-Proven with `oo` (eslider/go-onlyoffice) against the OnlyOffice portal
-(`office.produktor.io`). Portal CRM is the SSOT for company ↔ person ↔
-project associations; the corpus SoT (`eslider/cv/projects/knowledge-mesh-seed.yaml`)
-is the second, independent source. Facts that can be backed by both are
-written to the brain under `root=facts` by `bin/facts/crm`.
-
-## What was verified
-
-- Logical counts (portal MySQL): 1300 contacts = 897 persons + 404 companies,
-  198 projects, 998 deals, 939 project↔contact links.
-- Every client company linked to a project has ≥1 person underneath.
-- Every person `company_id` resolves to an existing company.
-- Corpus org list (9) maps 1:1 onto CRM companies:
-  ProProdukt SL / produktor.io, Dyvenia, Immowelt AG, WhereGroup,
-  Keynote SIGOS, D2S/SYSTEMS, GRID, Pack und Cup, Markets Platform.
-- 78 person↔company association facts written to the brain
-  (`how=crm-crosscheck`, `type=association`). Recall@5 in `bin/kb/eval` = 1.0.
-
-## Mistakes found
-
-| # | Mistake | Fix |
-|---|---------|-----|
-| 1 | Duplicate legal entity `GoldenRatio.Exchange` (contact 759) vs `Golden Ratio Exchange` (763); 3 deals (211, 287, 559) were linked to 759 | `oo contacts merge 759 763` — 763 kept, 759 removed, deal links re-pointed to 763 |
-| 2 | `env/`-wide: OnlyOffice creds file used wrong UX (user `eslider`, password with `$2` suffix) making `oo` auth fail | `.env` fixed to `eslider@gmail.com` + clean password; `.env` stays gitignored |
-
-## Gates after fix
-
-- `uv run python -m unittest discover -s bin/tools -t .` → 26 tests OK
-- `bin/facts/audit self` + `bin/facts/audit db` → ok
-- `bin/kb/eval` → recall@5 = 1.0
-- `go test ./...` (bin/server + bin/watch) → ok

docs/design.md

@@ -61,4 +61,19 @@ corpus HEAD.
 - C: narrative — READMEs, AGENTS.md, docs
 
 Confirmed = A×B or B×C agreement. Single source = hypothesis + `(not confirmed)`.
-Conflicting pairings (≥2 yes vs ≥2 no) = hypothesis (OQ1 → v2 resolution).
+Conflicting pairings (≥2 yes vs ≥2 no) = hypothesis (OQ1 → v2 resolution).
+
+## Read path
+
+`bin/brain/get.go`, `stats.go`, and `eval.go` call `internal/brain` with cgo
+(`system_ladybug`). They do not exec Python. Control questions for recall@5
+live in `internal/brain/rank` so CI can test the table without libladybug.
+Python `bin/kb/{get,stats,eval}` remain for GitHub Actions until the runner
+has ladybug cgo. Index/write is still `bin/kb/index`.
+
+## Agent API (D20)
+
+`bin/brain/serve.go` exposes the same `internal/httpapi.Ops` table as OpenAPI
+(`GET /openapi.json`) and MCP (`POST /mcp` JSON-RPC `tools/list` +
+`tools/call`). Tool names match paths: `search`, `get`, `stats`, `audit`.
+Agents should use these endpoints instead of shebang CLIs.

internal/brain/modelid.go

@@ -0,0 +1,3 @@
+package brain
+
+const ModelID = "minishlab/potion-multilingual-128M"

internal/brain/rank/evalq.go

@@ -0,0 +1,16 @@
+package rank
+
+// Eval control questions (recall@5). Kept here so CI can test the gate
+// table without ladybug cgo. The runner lives in internal/brain (cgo).
+const EvalRecallThreshold = 0.95
+
+type EvalQuestion struct {
+	Query    string
+	Fragment string
+}
+
+var EvalQuestions = []EvalQuestion{
+	{"hybrid search fts and vector", "BM25"},
+	{"eslider devops engineer", "DevOps"},
+	{"ladybugdb graph engine storage", "LadybugDB"},
+}

internal/brain/rank/evalq_test.go

@@ -0,0 +1,17 @@
+package rank
+
+import "testing"
+
+func TestEvalQuestionsAreThreeAndThreshold(t *testing.T) {
+	if EvalRecallThreshold != 0.95 {
+		t.Fatalf("threshold = %v", EvalRecallThreshold)
+	}
+	if len(EvalQuestions) != 3 {
+		t.Fatalf("questions = %d, want 3", len(EvalQuestions))
+	}
+	for _, q := range EvalQuestions {
+		if q.Query == "" || q.Fragment == "" {
+			t.Fatalf("empty control: %+v", q)
+		}
+	}
+}

internal/brain/read.go

@@ -0,0 +1,281 @@
+//go:build cgo && system_ladybug
+
+package brain
+
+import (
+	"encoding/json"
+	"fmt"
+	"os"
+	"sort"
+	"strings"
+	"unicode/utf8"
+
+	"github.com/eSlider/2dph/internal/brain/rank"
+)
+
+func MainGet(args []string) int {
+	id, body, jsonOut := "", false, false
+	for _, a := range args {
+		switch {
+		case a == "--body":
+			body = true
+		case a == "--json":
+			jsonOut = true
+		case a == "-h" || a == "--help":
+			fmt.Fprintln(os.Stderr, `usage: bin/brain/get.go <id> [--body] [--json]`)
+			return 0
+		case strings.HasPrefix(a, "-"):
+			fmt.Fprintf(os.Stderr, "brain/get: unknown flag %s\n", a)
+			return 2
+		default:
+			id = a
+		}
+	}
+	if id == "" {
+		fmt.Fprintln(os.Stderr, "brain/get: id required")
+		return 2
+	}
+	if err := openBrain(); err != nil {
+		fmt.Fprintf(os.Stderr, "open brain: %v\n", err)
+		return 1
+	}
+	defer closeBrain()
+	meta, text, err := lookupLeaf(id)
+	if err != nil {
+		fmt.Fprintf(os.Stderr, "brain/get: %v\n", err)
+		return 1
+	}
+	out := Dict{
+		{"id", meta["id"]},
+		{"root", meta["root"]},
+		{"confidence", meta["confidence"]},
+		{"source", meta["source"]},
+		{"type", meta["type"]},
+	}
+	if body {
+		out = append(out, KV{"text", text})
+	} else {
+		out = append(out, KV{"snippet", clip(text, 280)})
+	}
+	if jsonOut {
+		m := map[string]any{}
+		for _, kv := range out {
+			m[kv.K] = kv.V
+		}
+		enc := json.NewEncoder(os.Stdout)
+		enc.SetIndent("", "  ")
+		enc.SetEscapeHTML(false)
+		return b2i(enc.Encode(m))
+	}
+	fmt.Print(toYAML(out, 0))
+	return 0
+}
+
+func MainStats(args []string) int {
+	jsonOut := false
+	for _, a := range args {
+		switch a {
+		case "--json":
+			jsonOut = true
+		case "-h", "--help":
+			fmt.Fprintln(os.Stderr, `usage: bin/brain/stats.go [--json]`)
+			return 0
+		default:
+			if strings.HasPrefix(a, "-") {
+				fmt.Fprintf(os.Stderr, "brain/stats: unknown flag %s\n", a)
+				return 2
+			}
+		}
+	}
+	if err := openBrain(); err != nil {
+		fmt.Fprintf(os.Stderr, "open brain: %v\n", err)
+		return 1
+	}
+	defer closeBrain()
+	s, err := leafStats()
+	if err != nil {
+		fmt.Fprintf(os.Stderr, "brain/stats: %v\n", err)
+		return 1
+	}
+	if jsonOut {
+		enc := json.NewEncoder(os.Stdout)
+		enc.SetIndent("", "  ")
+		enc.SetEscapeHTML(false)
+		return b2i(enc.Encode(s))
+	}
+	by := s["by_root"].(map[string]int)
+	keys := make([]string, 0, len(by))
+	for k := range by {
+		keys = append(keys, k)
+	}
+	sort.Strings(keys)
+	byRoot := make(Dict, 0, len(keys))
+	for _, k := range keys {
+		byRoot = append(byRoot, KV{k, by[k]})
+	}
+	out := Dict{
+		{"total", s["total"]},
+		{"by_root", byRoot},
+		{"db", s["db"]},
+		{"model", s["model"]},
+	}
+	fmt.Print(toYAML(out, 0))
+	return 0
+}
+
+func MainEval(args []string) int {
+	jsonOut := false
+	for _, a := range args {
+		switch a {
+		case "--json":
+			jsonOut = true
+		case "-h", "--help":
+			fmt.Fprintln(os.Stderr, `usage: bin/brain/eval.go [--json]`)
+			return 0
+		default:
+			if strings.HasPrefix(a, "-") {
+				fmt.Fprintf(os.Stderr, "brain/eval: unknown flag %s\n", a)
+				return 2
+			}
+		}
+	}
+	if err := openBrain(); err != nil {
+		fmt.Fprintf(os.Stderr, "open brain: %v\n", err)
+		return 1
+	}
+	defer closeBrain()
+	recalled := 0
+	details := make([]any, 0, len(rank.EvalQuestions))
+	jsDetails := make([]map[string]any, 0, len(rank.EvalQuestions))
+	for _, q := range rank.EvalQuestions {
+		hits, err := queryFTS(q.Query, 5)
+		ok := false
+		if err == nil {
+			frag := strings.ToLower(q.Fragment)
+			for _, h := range hits {
+				if strings.Contains(strings.ToLower(h.Text), frag) {
+					ok = true
+					break
+				}
+			}
+		}
+		if ok {
+			recalled++
+		}
+		details = append(details, Dict{
+			{"q", q.Query},
+			{"fragment", q.Fragment},
+			{"in_top5", ok},
+		})
+		jsDetails = append(jsDetails, map[string]any{
+			"q": q.Query, "fragment": q.Fragment, "in_top5": ok,
+		})
+	}
+	n := len(rank.EvalQuestions)
+	recall := 0.0
+	if n > 0 {
+		recall = float64(recalled) / float64(n)
+	}
+	passed := recall >= rank.EvalRecallThreshold
+	if jsonOut {
+		enc := json.NewEncoder(os.Stdout)
+		enc.SetIndent("", "  ")
+		enc.SetEscapeHTML(false)
+		_ = enc.Encode(map[string]any{
+			"recall@5": round3(recall),
+			"passed":   passed,
+			"gate":     n,
+			"details":  jsDetails,
+		})
+	} else {
+		out := Dict{
+			{"recall@5", round3(recall)},
+			{"passed", passed},
+			{"gate", n},
+			{"details", details},
+		}
+		fmt.Print(toYAML(out, 0))
+	}
+	if !passed {
+		return 2
+	}
+	return 0
+}
+
+func lookupLeaf(id string) (map[string]string, string, error) {
+	if conn == nil {
+		return nil, "", fmt.Errorf("brain not open")
+	}
+	stmt, err := conn.Prepare(
+		"MATCH (l:Leaf {id:$id}) RETURN l.id, l.text, l.root, l.confidence, l.source, l.type",
+	)
+	if err != nil {
+		return nil, "", err
+	}
+	defer stmt.Close()
+	res, err := conn.Execute(stmt, map[string]any{"id": id})
+	if err != nil {
+		return nil, "", err
+	}
+	if !res.HasNext() {
+		return nil, "", fmt.Errorf("no leaf %s", id)
+	}
+	row, err := res.Next()
+	if err != nil {
+		return nil, "", err
+	}
+	vals, err := row.GetAsSlice()
+	if err != nil || len(vals) < 6 {
+		return nil, "", fmt.Errorf("leaf row")
+	}
+	meta := map[string]string{
+		"id":         fmt.Sprint(vals[0]),
+		"root":       fmt.Sprint(vals[2]),
+		"confidence": fmt.Sprint(vals[3]),
+		"source":     fmt.Sprint(vals[4]),
+		"type":       fmt.Sprint(vals[5]),
+	}
+	return meta, fmt.Sprint(vals[1]), nil
+}
+
+func leafStats() (map[string]any, error) {
+	if conn == nil {
+		return nil, fmt.Errorf("brain not open")
+	}
+	res, err := conn.Query("MATCH (l:Leaf) RETURN l.root, count(*)")
+	if err != nil {
+		return nil, err
+	}
+	byRoot := map[string]int{}
+	total := 0
+	for res.HasNext() {
+		row, err := res.Next()
+		if err != nil {
+			return nil, err
+		}
+		vals, err := row.GetAsSlice()
+		if err != nil || len(vals) < 2 {
+			continue
+		}
+		n := int(asInt(vals[1]))
+		byRoot[fmt.Sprint(vals[0])] = n
+		total += n
+	}
+	return map[string]any{
+		"total":   total,
+		"by_root": byRoot,
+		"db":      dbPath(),
+		"model":   ModelID,
+	}, nil
+}
+
+func clip(s string, n int) string {
+	if utf8.RuneCountInString(s) <= n {
+		return s
+	}
+	return string([]rune(s)[:n])
+}
+
+func round3(f float64) float64 {
+	return float64(int(f*1000+0.5)) / 1000
+}

internal/httpapi/mcp.go

@@ -0,0 +1,185 @@
+package httpapi
+
+import (
+	"encoding/json"
+	"fmt"
+	"io"
+	"net/http"
+	"strconv"
+	"strings"
+)
+
+type rpcReq struct {
+	JSONRPC string          `json:"jsonrpc"`
+	ID      json.RawMessage `json:"id"`
+	Method  string          `json:"method"`
+	Params  json.RawMessage `json:"params"`
+}
+
+type rpcErr struct {
+	Code    int    `json:"code"`
+	Message string `json:"message"`
+}
+
+func (s *Server) handleOpenAPI(w http.ResponseWriter, _ *http.Request) {
+	writeJSON(w, http.StatusOK, OpenAPI())
+}
+
+func (s *Server) handleMCP(w http.ResponseWriter, r *http.Request) {
+	if r.Method != http.MethodPost {
+		writeJSON(w, http.StatusMethodNotAllowed, map[string]any{"error": "POST JSON-RPC"})
+		return
+	}
+	raw, err := io.ReadAll(io.LimitReader(r.Body, 1<<20))
+	if err != nil {
+		writeJSON(w, http.StatusBadRequest, map[string]any{"error": "read body"})
+		return
+	}
+	var req rpcReq
+	if err := json.Unmarshal(raw, &req); err != nil {
+		writeJSON(w, http.StatusOK, rpcResult(nil, nil, &rpcErr{-32700, "parse error"}))
+		return
+	}
+	result, rpcErrv, callErr := s.mcpDispatch(r, req)
+	if callErr != nil {
+		writeJSON(w, http.StatusOK, rpcResult(req.ID, nil, &rpcErr{-32603, callErr.Error()}))
+		return
+	}
+	writeJSON(w, http.StatusOK, rpcResult(req.ID, result, rpcErrv))
+}
+
+func (s *Server) mcpDispatch(r *http.Request, req rpcReq) (any, *rpcErr, error) {
+	switch req.Method {
+	case "initialize":
+		return map[string]any{
+			"protocolVersion": "2024-11-05",
+			"capabilities":    map[string]any{"tools": map[string]any{}},
+			"serverInfo":      map[string]any{"name": "2dph", "version": "1"},
+		}, nil, nil
+	case "notifications/initialized", "notifications/cancelled":
+		return map[string]any{}, nil, nil
+	case "tools/list":
+		return map[string]any{"tools": MCPTools()}, nil, nil
+	case "tools/call":
+		out, err := s.mcpCall(r, req.Params)
+		return out, nil, err
+	case "ping":
+		return map[string]any{}, nil, nil
+	default:
+		return nil, &rpcErr{-32601, "method not found"}, nil
+	}
+}
+
+func (s *Server) mcpCall(r *http.Request, params json.RawMessage) (any, error) {
+	var p struct {
+		Name      string         `json:"name"`
+		Arguments map[string]any `json:"arguments"`
+	}
+	if err := json.Unmarshal(params, &p); err != nil {
+		return nil, fmt.Errorf("params")
+	}
+	if p.Arguments == nil {
+		p.Arguments = map[string]any{}
+	}
+	var (
+		body []byte
+		err  error
+	)
+	switch p.Name {
+	case "search":
+		q := strings.TrimSpace(fmt.Sprint(p.Arguments["q"]))
+		if q == "" || q == "<nil>" {
+			return mcpText(`{"error":"q required"}`, true), nil
+		}
+		limit := 10
+		if raw, ok := p.Arguments["n"]; ok {
+			switch n := raw.(type) {
+			case float64:
+				limit = int(n)
+			case string:
+				if v, e := strconv.Atoi(n); e == nil {
+					limit = v
+				}
+			}
+		}
+		if limit < 1 || limit > 100 {
+			return mcpText(`{"error":"n must be int 1..100"}`, true), nil
+		}
+		if !s.tryAcquire(r) {
+			return nil, fmt.Errorf("cancelled")
+		}
+		defer s.release()
+		body, err = s.api.Search(r.Context(), q, limit)
+	case "get":
+		id := strings.TrimSpace(fmt.Sprint(p.Arguments["id"]))
+		if id == "" || id == "<nil>" {
+			return mcpText(`{"error":"id required"}`, true), nil
+		}
+		full := false
+		switch v := p.Arguments["body"].(type) {
+		case bool:
+			full = v
+		case string:
+			full = v == "1" || v == "true"
+		}
+		if !s.tryAcquire(r) {
+			return nil, fmt.Errorf("cancelled")
+		}
+		defer s.release()
+		body, err = s.api.Get(r.Context(), id, full)
+	case "stats":
+		if !s.tryAcquire(r) {
+			return nil, fmt.Errorf("cancelled")
+		}
+		defer s.release()
+		body, err = s.api.Stats(r.Context())
+	case "audit":
+		if !s.tryAcquire(r) {
+			return nil, fmt.Errorf("cancelled")
+		}
+		defer s.release()
+		body, err = s.api.Audit(r.Context())
+	case "ingest":
+		if !s.tryAcquire(r) {
+			return nil, fmt.Errorf("cancelled")
+		}
+		defer s.release()
+		body, err = s.api.Ingest(r.Context())
+	default:
+		return nil, fmt.Errorf("unknown tool %s", p.Name)
+	}
+	if err != nil {
+		return mcpText(err.Error(), true), nil
+	}
+	return mcpText(string(body), false), nil
+}
+
+func mcpText(text string, isError bool) map[string]any {
+	return map[string]any{
+		"content": []any{map[string]any{"type": "text", "text": text}},
+		"isError": isError,
+	}
+}
+
+type rpcResp struct {
+	JSONRPC string          `json:"jsonrpc"`
+	ID      json.RawMessage `json:"id"`
+	Result  any             `json:"result,omitempty"`
+	Error   *rpcErr         `json:"error,omitempty"`
+}
+
+func rpcResult(id json.RawMessage, result any, err *rpcErr) rpcResp {
+	out := rpcResp{JSONRPC: "2.0", ID: id}
+	if len(id) == 0 {
+		out.ID = []byte("null")
+	}
+	if err != nil {
+		out.Error = err
+		return out
+	}
+	if result == nil {
+		result = map[string]any{}
+	}
+	out.Result = result
+	return out
+}

internal/httpapi/server.go

@@ -48,18 +48,22 @@ func NewServer(api API, workers int) http.Handler {
 
 func (s *Server) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 	switch r.URL.Path {
-	case "/health":
+	case PathHealth:
 		writeJSON(w, http.StatusOK, map[string]any{"status": "ok"})
-	case "/search":
+	case PathSearch:
 		s.handleSearch(w, r)
-	case "/get":
+	case PathGet:
 		s.handleGet(w, r)
-	case "/stats":
+	case PathStats:
 		s.handleJSON(w, r, s.api.Stats)
-	case "/audit":
+	case PathAudit:
 		s.handleJSON(w, r, s.api.Audit)
-	case "/ingest":
+	case PathIngest:
 		s.handleJSON(w, r, s.api.Ingest)
+	case PathOpenAPI:
+		s.handleOpenAPI(w, r)
+	case PathMCP:
+		s.handleMCP(w, r)
 	default:
 		writeJSON(w, http.StatusNotFound, map[string]any{"error": "not found"})
 	}
@@ -112,6 +116,16 @@ func (s *Server) handleJSON(w http.ResponseWriter, r *http.Request, fn func(cont
 	writeAPI(w, body, err)
 }
 
+func (s *Server) tryAcquire(r *http.Request) bool {
+	return s.acquire(nopWriter{}, r)
+}
+
+type nopWriter struct{}
+
+func (nopWriter) Header() http.Header       { return http.Header{} }
+func (nopWriter) Write([]byte) (int, error) { return 0, nil }
+func (nopWriter) WriteHeader(int)           {}
+
 func (s *Server) acquire(w http.ResponseWriter, r *http.Request) bool {
 	select {
 	case s.semaphore <- struct{}{}:

internal/httpapi/spec.go

@@ -0,0 +1,126 @@
+package httpapi
+
+// Shared HTTP surface: OpenAPI paths and MCP tools are generated from Ops.
+// ServeHTTP must keep the same path strings.
+
+type Param struct {
+	Name, In, Type, Description string
+	Required                    bool
+}
+
+type Op struct {
+	Path, Method, ID, Summary string
+	Params                    []Param
+	MCP                       bool
+}
+
+const (
+	PathHealth  = "/health"
+	PathSearch  = "/search"
+	PathGet     = "/get"
+	PathStats   = "/stats"
+	PathAudit   = "/audit"
+	PathIngest  = "/ingest"
+	PathOpenAPI = "/openapi.json"
+	PathMCP     = "/mcp"
+)
+
+var Ops = []Op{
+	{Path: PathHealth, Method: "get", ID: "health", Summary: "liveness"},
+	{
+		Path: PathSearch, Method: "get", ID: "search", Summary: "deduction search (facts → info → web)",
+		MCP: true,
+		Params: []Param{
+			{Name: "q", In: "query", Type: "string", Description: "search query", Required: true},
+			{Name: "n", In: "query", Type: "integer", Description: "hit limit 1..100 (default 10)"},
+		},
+	},
+	{
+		Path: PathGet, Method: "get", ID: "get", Summary: "read one leaf by id",
+		MCP: true,
+		Params: []Param{
+			{Name: "id", In: "query", Type: "string", Description: "leaf id", Required: true},
+			{Name: "body", In: "query", Type: "boolean", Description: "include full text"},
+		},
+	},
+	{Path: PathStats, Method: "get", ID: "stats", Summary: "index health", MCP: true},
+	{Path: PathAudit, Method: "get", ID: "audit", Summary: "facts confidence histogram", MCP: true},
+	{Path: PathIngest, Method: "get", ID: "ingest", Summary: "rebuild hint (write is v2)", MCP: true},
+	{Path: PathOpenAPI, Method: "get", ID: "openapi", Summary: "OpenAPI 3 document for this server"},
+}
+
+func OpenAPI() map[string]any {
+	paths := map[string]any{}
+	for _, op := range Ops {
+		params := make([]any, 0, len(op.Params))
+		for _, p := range op.Params {
+			params = append(params, map[string]any{
+				"name":        p.Name,
+				"in":          p.In,
+				"required":    p.Required,
+				"description": p.Description,
+				"schema":      map[string]any{"type": p.Type},
+			})
+		}
+		item := map[string]any{
+			"operationId": op.ID,
+			"summary":     op.Summary,
+			"responses": map[string]any{
+				"200": map[string]any{
+					"description": "JSON",
+					"content": map[string]any{
+						"application/json": map[string]any{
+							"schema": map[string]any{"type": "object"},
+						},
+					},
+				},
+			},
+		}
+		if len(params) > 0 {
+			item["parameters"] = params
+		}
+		paths[op.Path] = map[string]any{op.Method: item}
+	}
+	return map[string]any{
+		"openapi": "3.0.3",
+		"info": map[string]any{
+			"title":       "2dph brain",
+			"version":     "1",
+			"description": "Same handlers as bin/brain/serve.go. MCP tools at POST /mcp match these paths.",
+		},
+		"paths": paths,
+	}
+}
+
+type MCPTool struct {
+	Name        string         `json:"name"`
+	Description string         `json:"description"`
+	InputSchema map[string]any `json:"inputSchema"`
+}
+
+func MCPTools() []MCPTool {
+	out := make([]MCPTool, 0, len(Ops))
+	for _, op := range Ops {
+		if !op.MCP {
+			continue
+		}
+		props := map[string]any{}
+		var required []string
+		for _, p := range op.Params {
+			props[p.Name] = map[string]any{"type": p.Type, "description": p.Description}
+			if p.Required {
+				required = append(required, p.Name)
+			}
+		}
+		schema := map[string]any{"type": "object", "properties": props}
+		if len(required) > 0 {
+			schema["required"] = required
+		}
+		out = append(out, MCPTool{
+			Name:        op.ID,
+			Description: op.Summary,
+			InputSchema: schema,
+		})
+	}
+	return out
+}

internal/httpapi/spec_test.go

@@ -0,0 +1,86 @@
+package httpapi
+
+import (
+	"encoding/json"
+	"net/http"
+	"net/http/httptest"
+	"strings"
+	"testing"
+)
+
+func TestOpenAPIIncludesCorePaths(t *testing.T) {
+	doc := OpenAPI()
+	raw, err := json.Marshal(doc)
+	if err != nil {
+		t.Fatal(err)
+	}
+	paths, _ := doc["paths"].(map[string]any)
+	for _, p := range []string{"/search", "/get", "/stats", "/audit"} {
+		if _, ok := paths[p]; !ok {
+			t.Fatalf("openapi missing path %s (%s)", p, raw)
+		}
+	}
+}
+
+func TestMCPToolsMatchOpenAPIPaths(t *testing.T) {
+	paths, _ := OpenAPI()["paths"].(map[string]any)
+	tools := MCPTools()
+	if len(tools) == 0 {
+		t.Fatal("no MCP tools")
+	}
+	names := map[string]bool{}
+	for _, tool := range tools {
+		names[tool.Name] = true
+		path := "/" + tool.Name
+		if _, ok := paths[path]; !ok {
+			t.Fatalf("MCP tool %s has no OpenAPI path %s", tool.Name, path)
+		}
+	}
+	for _, need := range []string{"search", "get", "stats", "audit"} {
+		if !names[need] {
+			t.Fatalf("MCP tools missing %s: %v", need, names)
+		}
+	}
+}
+
+func TestOpenAPIHTTP(t *testing.T) {
+	h := NewServer(&fakeSearcher{}, 1)
+	code, body := get(t, h, "/openapi.json")
+	if code != http.StatusOK {
+		t.Fatalf("code = %d body=%s", code, body)
+	}
+	var doc map[string]any
+	if err := json.Unmarshal(body, &doc); err != nil {
+		t.Fatalf("not json: %v", err)
+	}
+	if doc["openapi"] == nil {
+		t.Fatalf("missing openapi version: %s", body)
+	}
+}
+
+func TestMCPToolsListAndCall(t *testing.T) {
+	h := NewServer(&fakeSearcher{}, 1)
+	code, body := postJSON(t, h, "/mcp", `{"jsonrpc":"2.0","id":1,"method":"tools/list"}`)
+	if code != http.StatusOK {
+		t.Fatalf("list code = %d body=%s", code, body)
+	}
+	if !strings.Contains(string(body), `"search"`) {
+		t.Fatalf("tools/list missing search: %s", body)
+	}
+	code, body = postJSON(t, h, "/mcp", `{"jsonrpc":"2.0","id":2,"method":"tools/call","params":{"name":"search","arguments":{"q":"matrix","n":3}}}`)
+	if code != http.StatusOK {
+		t.Fatalf("call code = %d body=%s", code, body)
+	}
+	if !strings.Contains(string(body), "matrix") {
+		t.Fatalf("search call body %s", body)
+	}
+}
+
+func postJSON(t *testing.T, h http.Handler, path, raw string) (int, []byte) {
+	t.Helper()
+	req := httptest.NewRequest(http.MethodPost, path, strings.NewReader(raw))
+	req.Header.Set("Content-Type", "application/json")
+	rec := httptest.NewRecorder()
+	h.ServeHTTP(rec, req)
+	return rec.Code, rec.Body.Bytes()
+}

skills/brain/SKILL.md

@@ -28,7 +28,7 @@ bin/brain/search.go "onlyoffice postgres" --root facts # restrict to confirmed
 bin/brain/search.go "where is cs-lexicon" --json | yq '.[].ref'
 bin/brain/get.go <id> --body                           # full chunk only when needed
 bin/brain/stats.go                                     # index health
-bin/brain/eval.go                                      # recall@5 >= 0.95 gate
+bin/brain/eval.go                                      # recall@5 >= 0.95 gate (Go; Python bin/kb/eval is CI fallback)
 ```
 
 `bin/kb/search` is a deprecated wrapper. `--hop` errors (File/FROM_FILE edges
@@ -44,4 +44,6 @@ are not wired yet); do not treat it as a graph walk.
   are not evidence of absence. `--root facts|info` and `--no-web` skip the web.
 - If recall looks wrong, run `bin/brain/eval.go`; it gates control questions and
   should stay at or above 95% recall@5.
+- Agents: `GET /openapi.json` and `POST /mcp` on `bin/brain/serve.go` (same
+  handlers; tool names match paths `search`/`get`/`stats`/`audit`).
 - Never report an unconfirmed single-source local answer as fact.