When a Claude (or any other MCP client) connects to a project's mcplocal
endpoint, every Agent attached to that project now appears in the
session's tools/list as a virtual MCP server named `agent-<agentName>`
with one tool `chat`. Calling that tool POSTs to the Stage 3 chat
endpoint and returns the assistant's reply as MCP content. The tool's
description is the agent's own description, so connecting clients see
prose like "I review security design — ask me after each major change."
This is what makes one agent reachable from another's MCP session.
Plumbing:
* src/mcplocal/src/proxymodel/plugins/agents.ts (new) — the plugin.
onSessionCreate fetches /api/v1/projects/:p/agents via mcpd, then
registers a VirtualServer per agent. The chat tool's inputSchema
mirrors the LiteLLM-style override surface (temperature, top_p,
top_k, max_tokens, stop, seed, tools_allowlist, extra) plus
threadId for follow-ups. Namespace collision with an existing
upstream MCP server named `agent-<x>` is detected and skipped with
a `ctx.log.warn` line — better to surface the conflict than to
silently shadow real tool entries in the virtualTools map.
* src/mcplocal/src/proxymodel/plugins/compose.ts (new) — generic
N-plugin composition helper. Lifecycle hooks fan out in order;
transform hooks (onToolsList, onResourcesList, onPromptsList,
onToolCallAfter) pipeline; intercept hooks (onToolCallBefore,
onResourceRead, onPromptGet, onInitialize) short-circuit on the
first non-null. Generalizes what createDefaultPlugin does for
two fixed parents.
* src/mcplocal/src/http/project-mcp-endpoint.ts — every project
session now uses composePlugins([defaultPlugin, agentsPlugin]) so
agents show up no matter which proxymodel the project is on.
* Plugin context: added getFromMcpd(path) alongside postToMcpd. The
existing postToMcpd was hard-coded to POST; the agents plugin
needs GET to discover. Wired through plugin.ts → plugin-context.ts
→ router.ts.
Tests:
plugin-agents.test.ts (8) — registers per agent, falls back to a
generic description, skips on namespace collision, no-ops with
zero agents, logs and continues on mcpd error, chat handler
POSTs correct body and returns content array, isError surfacing
on mcpd error, onSessionDestroy unregisters everything.
plugin-compose.test.ts (6) — single-plugin pass-through, empty
rejection, lifecycle ordering, intercept short-circuit, list
pipeline, no-op composition stays minimal.
mcplocal suite: 715/715. mcpd suite still 759/759.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
285be11dd5