feat: MCP server `nous-mcp` exposing campaigns as resources + tools

[sriumcp]

TL;DR

Build an MCP server that exposes Nous campaigns as queryable resources and tools. Lets any Claude Code session — terminal, web, IDE — @-reference a campaign or call nous.search_principles("ordinal scheduling") natively, without bash plumbing.

Why this matters

On 5/20 the user explicitly tried to aggregate "all campaigns about saturation detection, with results and patches." The agent had to grep across inference-sim/.nous/*/findings.json manually. With 33 campaigns on inference-sim alone, this is acute. MCP is the canonical Claude Code answer to "give my agent access to my data."

What's already shipped

• The on-disk artifact layout (state.json, ledger.json, findings.json, patches/) is stable and well-tested. This issue just exposes it.

Proposed approach

Resources:

• nous://campaigns — list all campaigns with status
• nous://campaigns/<run-id>/state — current phase + iteration
• nous://campaigns/<run-id>/principles — accumulated principles
• nous://campaigns/<run-id>/iter/<N>/findings — findings.json
• nous://campaigns/<run-id>/iter/<N>/patches/<arm>.patch — code patch
• nous://campaigns/<run-id>/iter/<N>/results/<arm>/<seed> — raw result file

Tools:

• nous.list_campaigns(query?, status?, repo?) — filter campaigns
• nous.search_principles(text, scope?) — fuzzy/semantic search across principles.json files
• nous.get_arm_results(run_id, iter, arm) — return aggregated results for an arm
• nous.compare_iterations(run_id, iter_a, iter_b) — deterministic diff of findings

Acceptance criteria

• nous-mcp serve starts a local stdio MCP server.
• Drop-in config snippet for ~/.claude.json documented in README.
• In a fresh Claude Code session, the agent can answer "find campaigns about saturation detection and summarize their h-main outcomes" using only MCP calls.

Notes

• Optional: enable embedding-based semantic search when OPENAI_API_KEY is set; fall back to ripgrep otherwise.
• Keep the MCP server stateless; campaigns live on disk.

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Part of #120.

[sriumcp]

Closed by #153 (squash-merge 3e69b85, merged into reflective 2026-05-24). The merged commit message contains an explicit Closes #126. GitHub auto-close didn't fire because the PR targets reflective rather than the repo's default branch.