feat: add brain_query and brain_write MCP tools

Adds the brain skill that proxies HTTP calls to the ingestion server,
exposing brain_query (/query) and brain_write (/write) as MCP tools.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

internal/skills/brain/handlers.go

@@ -0,0 +1,90 @@
+// internal/skills/brain/handlers.go
+package brain
+
+import (
+	"bytes"
+	"context"
+	"encoding/json"
+	"fmt"
+	"io"
+	"net/http"
+)
+
+// Handle dispatches brain_query and brain_write tool calls.
+func (s *Skill) Handle(ctx context.Context, tool string, args json.RawMessage) (json.RawMessage, error) {
+	switch tool {
+	case "brain_query":
+		return s.query(ctx, args)
+	case "brain_write":
+		return s.write(ctx, args)
+	default:
+		return nil, fmt.Errorf("unknown brain tool: %s", tool)
+	}
+}
+
+type queryArgs struct {
+	Query string `json:"query"`
+	Limit int    `json:"limit,omitempty"`
+}
+
+func (s *Skill) query(ctx context.Context, args json.RawMessage) (json.RawMessage, error) {
+	var a queryArgs
+	if err := json.Unmarshal(args, &a); err != nil {
+		return nil, fmt.Errorf("parse args: %w", err)
+	}
+	if a.Query == "" {
+		return nil, fmt.Errorf("query is required")
+	}
+	if a.Limit == 0 {
+		a.Limit = 5
+	}
+	return s.post(ctx, "/query", a)
+}
+
+type writeArgs struct {
+	Content  string `json:"content"`
+	Type     string `json:"type,omitempty"`
+	Domain   string `json:"domain,omitempty"`
+	Filename string `json:"filename,omitempty"`
+}
+
+func (s *Skill) write(ctx context.Context, args json.RawMessage) (json.RawMessage, error) {
+	var a writeArgs
+	if err := json.Unmarshal(args, &a); err != nil {
+		return nil, fmt.Errorf("parse args: %w", err)
+	}
+	if a.Content == "" {
+		return nil, fmt.Errorf("content is required")
+	}
+	return s.post(ctx, "/write", map[string]string{
+		"content":  a.Content,
+		"filename": a.Filename,
+	})
+}
+
+func (s *Skill) post(ctx context.Context, path string, body any) (json.RawMessage, error) {
+	b, err := json.Marshal(body)
+	if err != nil {
+		return nil, fmt.Errorf("marshal request: %w", err)
+	}
+	req, err := http.NewRequestWithContext(ctx, http.MethodPost, s.cfg.IngestBaseURL+path, bytes.NewReader(b))
+	if err != nil {
+		return nil, fmt.Errorf("build request: %w", err)
+	}
+	req.Header.Set("Content-Type", "application/json")
+
+	resp, err := http.DefaultClient.Do(req)
+	if err != nil {
+		return nil, fmt.Errorf("call ingestion server: %w", err)
+	}
+	defer func() { _ = resp.Body.Close() }()
+
+	out, err := io.ReadAll(resp.Body)
+	if err != nil {
+		return nil, fmt.Errorf("read response: %w", err)
+	}
+	if resp.StatusCode != http.StatusOK {
+		return nil, fmt.Errorf("ingestion server returned %d: %s", resp.StatusCode, out)
+	}
+	return json.RawMessage(out), nil
+}

internal/skills/brain/handlers_test.go

@@ -0,0 +1,61 @@
+// internal/skills/brain/handlers_test.go
+package brain_test
+
+import (
+	"context"
+	"encoding/json"
+	"net/http"
+	"net/http/httptest"
+	"testing"
+
+	"github.com/mathiasbq/supervisor/internal/skills/brain"
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+func TestHandle_BrainQuery_CallsIngestServer(t *testing.T) {
+	called := false
+	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		assert.Equal(t, "/query", r.URL.Path)
+		called = true
+		json.NewEncoder(w).Encode(map[string]any{
+			"results": []map[string]any{
+				{"path": "wiki/concepts/tdd.md", "title": "TDD", "excerpt": "Test-driven development.", "score": 3},
+			},
+		})
+	}))
+	defer srv.Close()
+
+	s := brain.New(brain.Config{IngestBaseURL: srv.URL})
+	args, _ := json.Marshal(map[string]string{"query": "test driven development"})
+	out, err := s.Handle(context.Background(), "brain_query", args)
+	require.NoError(t, err)
+	assert.True(t, called)
+
+	var result map[string]any
+	require.NoError(t, json.Unmarshal(out, &result))
+	results := result["results"].([]any)
+	assert.Len(t, results, 1)
+}
+
+func TestHandle_BrainWrite_CallsIngestServer(t *testing.T) {
+	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		assert.Equal(t, "/write", r.URL.Path)
+		json.NewEncoder(w).Encode(map[string]string{"path": "raw/test.md"})
+	}))
+	defer srv.Close()
+
+	s := brain.New(brain.Config{IngestBaseURL: srv.URL})
+	args, _ := json.Marshal(map[string]string{"content": "# Test\n\nSome learning.", "type": "concept"})
+	out, err := s.Handle(context.Background(), "brain_write", args)
+	require.NoError(t, err)
+	var result map[string]string
+	require.NoError(t, json.Unmarshal(out, &result))
+	assert.Equal(t, "raw/test.md", result["path"])
+}
+
+func TestHandle_UnknownTool_ReturnsError(t *testing.T) {
+	s := brain.New(brain.Config{IngestBaseURL: "http://localhost:3300"})
+	_, err := s.Handle(context.Background(), "brain_unknown", nil)
+	assert.Error(t, err)
+}

internal/skills/brain/skill.go

@@ -0,0 +1,55 @@
+// internal/skills/brain/skill.go
+package brain
+
+import (
+	"encoding/json"
+
+	"github.com/mathiasbq/supervisor/internal/registry"
+)
+
+// Config holds brain skill configuration.
+type Config struct {
+	IngestBaseURL string // base URL of the ingestion HTTP server, e.g. http://localhost:3300
+}
+
+// Skill implements registry.Skill for brain_query and brain_write.
+type Skill struct {
+	cfg Config
+}
+
+// New constructs a brain Skill.
+func New(cfg Config) *Skill { return &Skill{cfg: cfg} }
+
+// Name returns the skill name used for routing.
+func (s *Skill) Name() string { return "brain" }
+
+// Tools returns the MCP tool definitions for brain_query and brain_write.
+func (s *Skill) Tools() []registry.ToolDef {
+	schema := func(required []string, props map[string]any) json.RawMessage {
+		b, _ := json.Marshal(map[string]any{"type": "object", "required": required, "properties": props})
+		return b
+	}
+	str := map[string]any{"type": "string"}
+	num := map[string]any{"type": "integer"}
+
+	return []registry.ToolDef{
+		{
+			Name:        "brain_query",
+			Description: "Search the hyperguild brain wiki for relevant knowledge. Call this before starting any significant task.",
+			InputSchema: schema([]string{"query"}, map[string]any{
+				"query": str,
+				"limit": num,
+			}),
+		},
+		{
+			Name:        "brain_write",
+			Description: "Write a raw knowledge note to the brain for later ingestion into the wiki.",
+			InputSchema: schema([]string{"content"}, map[string]any{
+				"content":  str,
+				"type":     str,
+				"domain":   str,
+				"filename": str,
+			}),
+		},
+	}
+}