Index Agentica

indexagentica-mcp

Remote MCP server (Streamable HTTP) and REST search API for Index Agentica, the agent-first directory of skills, harnesses, MCP servers, tools, protocols and APIs, plus its long-form guides, comparisons, stacks and downloadable Agent Skills. Runs on Cloudflare Workers (free plan), stateless, no Durable Objects, no auth, CORS open. Read-only except request_listing / POST /v1/requests, which queue a listing request for Curator review (D1).

Self-hosting: see SELF_HOSTING.md to run your own copy from a fresh clone (template config, your own KV/D1, your own data mirror, local and remote smoke tests). wrangler.toml and DEPLOY.md are the maintainers' own deployment.

Install

Remote server: no install, no API key. Streamable HTTP at https://mcp.indexagentica.com/mcp (live).

claude mcp add --transport http indexagentica https://mcp.indexagentica.com/mcp

Other clients: add the URL as a Streamable HTTP server with no auth (see llms-install.md). The same Worker also answers at https://indexagentica-mcp.indexagentica.workers.dev/mcp (see DEPLOY.md).

Endpoints

Errors are always JSON: {"error":{"status":400,"code":"bad_request","message":"..."}} (codes: bad_request, not_found, method_not_allowed, rate_limited, upstream_error).

MCP tools

Every tool has a JSON-Schema inputSchema, an outputSchema, readOnlyHint annotations, and returns both structuredContent and the same JSON as a text content block. Bad arguments and unknown ids come back as isError: true tool results (so the model can correct itself); an unknown tool name is JSON-RPC -32602 whose message lists the valid tools and, when one is a clear match (client namespace prefixes such as mcp__indexagentica__search, synonyms such as search_index/find, typos within edit distance 2), suggests it: error.data = {requested, valid_tools, suggestion?}. Suggestions are never executed. Explicit aliases (TOOL_ALIASES in src/tools.js) are only added for unambiguous names real clients were observed calling, are not advertised in tools/list, and the originally requested name is what gets logged (detail = alias: ).

Scoring: per query word, exact id/name match 12, id segment 6, name substring 5, exact tag 4 (partial tag 2), summary 2, category 1.5, description 1; +8 if the whole phrase is in the name; multiplied by the fraction of words matched.

Protocol support (dual-era, stateless)

• 2026-07-28 (current spec, "modern"): no handshake. Each POST carries _meta["io.modelcontextprotocol/protocolVersion"] and the MCP-Protocol-Version, Mcp-Method (and for tools/call, Mcp-Name, base64 sentinel supported) headers. The server validates headers against the body (-32020 HeaderMismatch), rejects unknown versions with -32022 + supported list, implements server/discover, returns resultType: "complete", serverInfo in result _meta, and ttlMs/cacheScope caching hints on tools/list and server/discover. Unknown methods -> HTTP 404 + -32601.
• 2025-11-25 / 2025-06-18 / 2025-03-26 ("legacy"): initialize is answered (version negotiated, falling back to 2025-11-25), notifications/initialized -> 202, ping, tools/list, tools/call; 2025-03-26 batches are accepted. No `Mcp-Session-Id` is ever issued, so every request is independent and any Worker isolate can serve it.
• Responses are always application/json (never SSE). Origin is checked against ALLOWED_ORIGINS (default * because the data is public and read-only).

Spec refs: Streamable HTTP 2026-07-28, Versioning / dual-era, server/discover.

Data & caching

Source of truth is the published static site: GET https://indexagentica.com/api/index.json (all entries + categories) and GET /api/longform.json (long-form metadata), fetched together; if the long-form index can't be loaded, entries keep working. get_content fetches /api/longform/ / .json on demand (same cache), always from DATA_BASE_URL. The Worker keeps the indexes in isolate memory for CACHE_TTL_SECONDS (600 s), also stores it in the Cloudflare Cache API (effective on a custom domain; a no-op on workers.dev), coalesces concurrent refreshes, and serves the stale copy if the upstream fetch fails. New categories added by the site build appear automatically. Nothing is written anywhere.

Usage logging (Workers Analytics Engine)

Each request (except OPTIONS, /health, /robots.txt, /favicon.ico, /hit, /stats) writes one data point to the Analytics Engine dataset `indexagentica_mcp` (binding ANALYTICS in wrangler.toml), so we can count agent usage per tool and client. If the binding is missing (local tests, the ratelimit-test env), logging is a no-op, and a failing write never affects the response. Workers Free includes 100,000 data points written per day (pricing); data is kept for 3 months (limits).

Privacy: no IP addresses, no search query text