feat(glama): standalone nyxid-mcp-demo crate (refs #593)

[kaiweijw]

Summary

• New mcp-demo/ workspace crate producing nyxid-mcp-demo — a tiny standalone stdio MCP server for directory-listing introspection (Glama).
• Single dependency: serde_json. Cold cargo build: ~4 seconds (vs. 10-15+ min for the full backend, which was timing out on Glama's runners).
• Stripped binary size: ~530 KB.
• Mirrors the same four curated gateway tools the backend already exposes via nyxid mcp-demo: nyx_proxy_request, nyx_list_services, nyx_request_approval, nyx_exchange_identity. No duplication of intent — the same surface, shipped two ways.
• Updates Dockerfile.glama as the reference for what to paste into Glama's admin Dockerfile UI (Glama does not auto-read it from the repo).

Why a separate crate

Glama runners are timing out trying to build nyxid from scratch — the backend pulls 400+ transitive crates (mongodb, axum, jsonwebtoken with aws_lc_rs requiring cmake/clang, etc.). The directory's scoring pipeline only needs tools/list over stdio, so we don't need any of that machinery to be on the same compile path.

The standalone crate has just serde_json as a direct dep (~5 transitive crates total). Builds in seconds, runs from a 530K binary, doesn't share state or build deps with the production backend.

The backend's nyxid mcp-demo subcommand is left in place — useful for production self-discovery on real installs and harmless to keep.

Verification

$ cargo build --release -p nyxid-mcp-demo
   Compiling serde_core v1.0.228
   Compiling serde_json v1.0.149
   Compiling memchr v2.8.0
   Compiling itoa v1.0.18
   Compiling nyxid-mcp-demo v0.1.0
    Finished `release` profile [optimized] target(s) in 3.83s

$ printf '{"jsonrpc":"2.0","id":1,"method":"tools/list"}\n' \
    | ./target/release/nyxid-mcp-demo \
    | jq '.result.tools | length'
4

Full workspace still builds clean (cargo build --release -p nyxid -p nyxid-cli -p nyxid-mcp-demo finished in 2m 54s on M2). Pre-commit hooks (cargo fmt + clippy) passed locally.

Post-merge steps

1. Update Glama's admin UI build steps and CMD (single entry, references main post-merge).
2. Trigger Glama re-evaluation; verify tools/list introspection lands a real score.
3. Update punkpeye/awesome-mcp-servers#5485 entry with the inline badge per @punkpeye's format.

Test plan

• CI: cargo build, cargo test, cargo clippy, cargo fmt --check (pre-commit hooks already passed locally)
• Manual: nyxid-mcp-demo responds to initialize, tools/list, ping, and unknown methods (-32601)
• Manual: docker build -f Dockerfile.glama . reproduces the Glama config and the resulting image speaks stdio MCP
• After merge: Glama build completes within timeout, listing scored