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MNS MCP BRIDGE

Mobius MCP Bridge — Doctrine (C-286)

What it is

Every repo in the Mobius Neural Substrate (MNS) that declares mesh.mcp.enabled: true in mobius.yaml is simultaneously:

  1. A mesh node — identity, covenant, ledger feed, MII posture (see MNS Protocol).
  2. An MCP server manifest — tools, transport, base URL, and integrity rules that AI clients can consume without repo-specific guesswork.
  3. An integrity-governed capability surface — when the runtime implements the bridge, tool invocations should be attributable, GI-gated where declared, and written to the civic ledger / EPICON feed according to policy.

Why this matters

Without a declared MCP surface, agents call HTTP helpers ad hoc. There is no shared schema for which tools exist, who may invoke them, or what ledger record should exist afterward.

With mesh.mcp, the same file that registers the node in the mesh also describes the MCP contract. Discovery is centralized in:

  • mesh/mcp-discovery.json — mesh-wide index (regenerated in CI).
  • .well-known/mcp.json — stable well-known pointer at the Substrate root (raw GitHub URL for agents that only know the cortex).

Signal flow (target architecture)

AI agent (Cursor, Claude, Codex, …)
    |
    | fetch .well-known/mcp.json or mesh/mcp-discovery.json
    v
POST {node}/api/mcp  (streamable HTTP MCP)
    |
    | handler enforces mesh.mcp.integrity + per-tool requires_gi_above
    v
Tool implementation (reads/writes KV, proxied HTTP, …)
    |
    v
Optional: logInvocation → EPICON / civic feed (when log_all_invocations: true)

Runtime implementation for the Mobius Civic AI Terminal belongs in the mobius-civic-ai-terminal repository (app/api/mcp/route.ts or equivalent). This Substrate repo carries the spec, discovery JSON, and CI that make the mesh legible.

Constitutional constraints (normative intent)

  • Read tools: may default to no GI floor; still log when log_all_invocations: true.
  • Write tools: declare requires_gi_above (for example 0.6) where ledger mutation is involved.
  • Governance / Seal-class tools: reserve higher gates in future EPICON; document them in mobius.yaml before enabling.

Adding MCP to a new repo

  1. Extend mobius.yaml with mesh.mcp (see mesh/mobius-yaml-spec.md).
  2. Implement the MCP HTTP route in that repo’s stack (Terminal: Next.js route handlers).
  3. Register the node in mesh/registry.json if not already listed.
  4. Let the hourly Substrate workflow refresh mesh/mcp-discovery.json and .well-known/mcp.json, or open a PR that runs node scripts/mesh-mcp-discovery.mjs locally and commits the outputs.

One-line canon

The tools do not only run — they declare how they may run.

See also: MNS Protocol v1, mesh/mobius-yaml-spec.md, mesh/mcp-discovery.json.

We heal as we walk.