docs: add core/mcp extraction plan

Move Go MCP server from go-ai + PHP MCP from php-mcp into
a single core/mcp repo producing the core-mcp binary.

Co-Authored-By: Virgil <virgil@lethean.io>

docs/plans/2026-03-09-core-mcp-extraction.md

@@ -0,0 +1,92 @@
+# core/mcp Extraction
+
+**Goal:** Consolidate MCP code into `core/mcp` — Go MCP server from go-ai + PHP MCP from php-mcp. Produces `core-mcp` binary.
+
+**Pattern:** Polyglot repo like `core/agent` — Go at root, PHP in `src/php/`, composer.json at root as `lthn/mcp`.
+
+---
+
+### Task 1: Create core/mcp repo on forge, clone locally
+
+- Create `core/mcp` repo on forge via API
+- Clone to `/Users/snider/Code/core/mcp/`
+- Add to `~/Code/go.work`
+
+### Task 2: Move Go MCP package from go-ai
+
+**Move:** `go-ai/mcp/` → `core/mcp/pkg/mcp/`
+
+All files: `mcp.go`, `registry.go`, `subsystem.go`, `bridge.go`, transports (stdio, tcp, unix), all `tools_*.go`, all `*_test.go`, `brain/`, `ide/`
+
+**Move:** `go-ai/cmd/mcpcmd/` → `core/mcp/cmd/mcpcmd/`
+**Move:** `go-ai/cmd/brain-seed/` → `core/mcp/cmd/brain-seed/`
+
+Create `go.mod` as `forge.lthn.ai/core/mcp`. Deps from go-ai: go-sdk, gorilla/websocket, go-ml, go-rag, go-inference, go-process, go-i18n, gin.
+
+Find-replace `forge.lthn.ai/core/go-ai/mcp` → `forge.lthn.ai/core/mcp/pkg/mcp` in all moved files.
+
+### Task 3: Create cmd/core-mcp/main.go
+
+```go
+package main
+
+import (
+    "forge.lthn.ai/core/cli/pkg/cli"
+    mcpcmd "forge.lthn.ai/core/mcp/cmd/mcpcmd"
+)
+
+func main() {
+    cli.Main(
+        cli.WithCommands("mcp", mcpcmd.AddMCPCommands),
+    )
+}
+```
+
+Add `.core/build.yaml`:
+```yaml
+project:
+  name: core-mcp
+  binary: core-mcp
+```
+
+### Task 4: Move PHP from php-mcp into src/php/
+
+Copy all PHP source from `/Users/snider/Code/core/php-mcp/` → `core/mcp/src/php/`
+
+Create `composer.json` at root:
+```json
+{
+    "name": "lthn/mcp",
+    "description": "Model Context Protocol server for Laravel + standalone Go binary",
+    "license": "EUPL-1.2",
+    "require": { "php": "^8.2", "lthn/php": "*" },
+    "autoload": { "psr-4": { "Core\\Mcp\\": "src/php/" } },
+    "replace": { "core/php-mcp": "self.version", "lthn/php-mcp": "self.version" }
+}
+```
+
+Add `.gitattributes` to exclude Go from composer dist.
+
+### Task 5: Update consumers
+
+- `core/agent` — change import `go-ai/mcp` → `core/mcp/pkg/mcp` in `pkg/loop/tools_mcp.go`
+- `core/cli` — change `go-ai/cmd/mcpcmd` → `core/mcp/cmd/mcpcmd` import
+- App `composer.json` — change `core/php-mcp` → `lthn/mcp`, VCS url → `core/mcp.git`
+
+### Task 6: Clean up go-ai
+
+- Delete `go-ai/mcp/` directory
+- Delete `go-ai/cmd/mcpcmd/` and `go-ai/cmd/brain-seed/`
+- Remove unused deps from go-ai's go.mod (go-sdk, websocket, etc.)
+- go-ai keeps: `ai/`, `cmd/{daemon,embed-bench,lab,metrics,rag,security}`
+
+### Task 7: Register on Packagist, verify
+
+- Submit `core/mcp` to Packagist as `lthn/mcp`
+- `go build ./cmd/core-mcp` — verify binary builds
+- `go test ./...` — verify tests pass
+- Archive `core/php-mcp` on forge
+
+---
+
+**Repos affected:** core/mcp (new), go-ai (shrinks), core/agent (import update), core/cli (import update), php-mcp (archived), app composer.json