Index Agentica

Read-only 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.

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

Method	Path	What
POST	/mcp	MCP Streamable HTTP endpoint (JSON-RPC 2.0, JSON responses)
GET/DELETE	/mcp	405 (no standalone SSE stream, no sessions)
GET	/	JSON self-description with links to the MCP endpoint, REST, llms.txt, docs
GET	/search?q=&type=&category=&tags=a,b&limit=	Ranked search over entries and long-form (type: entry, guide, comparison, stack, skill or all (default); category applies to entries; limit 1-50, default 10; tags are AND-ed)
GET	/entries/<id> (or <id>.json)	One full entry; 404 includes suggestions
GET	/entries	All ids
GET	/content/<type>/<id> (or <id>.json)	One guide, comparison, stack or skill: metadata + markdown (?include_html=1 adds HTML); 404 includes suggestions
GET	/content?type=	Published long-form items (metadata)
GET	/categories	Categories with counts
GET	/openapi.json	OpenAPI 3.1 for the REST API
GET	/.well-known/mcp/server-card.json	Static server card (Smithery scan fallback): serverInfo, authentication: {required: false}, the same tools as tools/list, empty resources/prompts
GET	/stats	Public usage stats (JSON): site page views, outbound clicks, skill downloads, MCP tool calls per tool, REST requests, agent/human split; last 24h, last 7 days, all time since the since timestamps. Cached 10 min. See Usage stats
GET	/v1/usage	Alias of /stats (used by the site; less likely to be caught by content-blocker filters)
POST	/v1/e	Alias of /hit (used by the site)
POST	/hit	Site usage beacon from indexagentica.com's inline script (origin-checked, strictly validated, 204). See Site beacons
GET	/health	Liveness (not rate limited)

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

Tool	Input	Output (structuredContent)
search	query (string), type? (entry|guide|comparison|stack|skill|all, default all), category? (slug; entries only), tags? (string[], all must match), limit? (1-50)	{query, type, category?, tags, limit, total, results[]}; each result has type, id, name, summary, url, tags, score, links, plus category (entries) or author, last_verified, entries (long-form)
get_entry	id (kebab-case)	{entry} (the full entry per the entry schema + links + longform back-references)
get_content	type (guide|comparison|stack|skill), id, include_html?	{content}: front matter, metadata, markdown (scheme links resolved to absolute URLs), links; comparisons add comparison (criteria, table, verdict), stacks add stack (use case, components), skills add skill_md (full SKILL.md) and links.zip / links.skill_md
list_categories	none	{total, generated, categories[{slug,name,description,count,html,json}]}

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.

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/<route>/<id>.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).

Column	Field	Notes
index1	<route>:<tool or method or endpoint>	e.g. mcp:search, rest:get_entry
blob1	route	mcp or rest
blob2	endpoint	normalized: /mcp, /search, /entries/{id}, /content/{type}/{id}, ..., other
blob3	JSON-RPC method	initialize, tools/call, batch, ... (MCP only)
blob4	tool	MCP tool name, or the REST equivalent (search, get_entry, get_content, list_content, list_categories)
blob5, blob6	client name, version	from initialize clientInfo or 2026-07-28 _meta["io.modelcontextprotocol/clientInfo"]; truncated to 64/32 chars
blob7	User-Agent	truncated to 128 chars
blob8, blob9	protocol version, era	modern / legacy
blob10	outcome	ok, error (HTTP ≥ 400, JSON-RPC error or isError tool result), rate_limited
blob11	detail	JSON-RPC error code, tool_error, or HTTP status
blob12, blob13	country, colo	from request.cf
blob14, blob15, blob16	type filter, category filter, target id	only kebab-case values (public catalog slugs/ids); anything else is stored as invalid
blob17	UA class	human (mainstream browser User-Agent) or agent (everything else: MCP clients, SDKs, curl, crawlers, headless browsers); see src/ua.js. Added 2026-10-03; earlier rows are classified from blob7 at query time
double1	HTTP status
double2	latency (ms)	wall time inside the Worker (Workers clocks advance on I/O)
double3	ASN	from request.cf.asn (network, not person)
double4	result count	search total
double5, double6	query length in characters, words

Privacy: no IP addresses, no search query text, no free-text tool arguments, no cookies or tokens (the server has none), and for site beacons no referrers, query strings or client identifiers. Clients are identified only by their self-reported name/version and a truncated User-Agent. Example query (SQL API): SELECT blob4 AS tool, blob5 AS client, SUM(_sample_interval) AS requests FROM indexagentica_mcp WHERE timestamp > NOW() - INTERVAL '1' DAY GROUP BY tool, client ORDER BY requests DESC.

Site beacons (POST /hit)

Every page of indexagentica.com carries a small inline script (no cookies, no localStorage, no identifiers, no third-party code). It is skipped when navigator.webdriver is set or the browser sends Do Not Track or Global Privacy Control. It sends, with navigator.sendBeacon (as text/plain, so no CORS preflight):

Event	Body	When
page view	{"t":"pageview","p":"/entries/x402/"}	page load; p is the page's canonical path (no query string, no referrer)
outbound click	{"t":"click","p":"/entries/x402/","id":"x402","h":"www.x402.org"}	click on a listing's website/repo/docs/source link on its entry page
download	{"t":"download","p":"/skills/<id>/","id":"<id>","k":"zip"|"skill_md"}	click on a skill zip or raw SKILL.md link

The site posts to the alias /v1/e on mcp.indexagentica.com and falls back to the same path on indexagentica-mcp.indexagentica.workers.dev if that fails (same Worker, same checks). The Worker accepts only Origin: https://indexagentica.com (HIT_ORIGINS), bodies up to 512 bytes, the three event types with exactly their fields, p from the set of pages the site publishes, ids that exist in the published index, and hosts that the entry actually links to. Anything else gets 400 and is not stored. /hit has its own rate-limit counter (same 120/min per IP). Accepted hits go to the separate dataset indexagentica_hits (binding HITS), index hit:<event>:

Column	Field
blob1	event: pageview, click, download
blob2	page path
blob3	entry or skill id (click, download)
blob4	destination host (click)
blob5	download kind: zip, skill_md
blob6	UA class (human / agent)
blob7	country (from request.cf)
double1	1

Usage stats (GET /stats)

Aggregates both datasets through the Analytics Engine SQL API using the secret CF_ANALYTICS_TOKEN (Account Analytics Read) and CF_ACCOUNT_ID. Counts are SUM(_sample_interval). Windows: last_24h, last_7d (rolling) and all_time. Because Analytics Engine keeps 3 months, a daily cron (30 0 * * *) stores each completed UTC day's totals in Workers KV (STATS_KV, key day:YYYY-MM-DD); all_time = stored days + a live query from the first day not yet stored (/stats also catches up missing days lazily). since.mcp_api (STATS_API_SINCE, first deploy with request logging) and since.site_beacon (STATS_BEACON_SINCE, deploy of the beacon) label where counting starts; nothing earlier is estimated or backfilled. Only the server's own tool names are published (anything else is unknown_tool). Responses are cached 10 minutes (Cache API + in-memory, Cache-Control: public, max-age=600). Without the token the endpoint answers {"status":"collecting", ...} with no numbers; if the SQL API fails, 503 {"status":"unavailable"}.

Rate limiting

• Default: 120 requests / 60 s per client IP, per Cloudflare location, via the Workers Rate Limiting binding ([[ratelimits]] in wrangler.toml, GA since Sept 2025; period must be 10 or 60 s). It is intentionally approximate (eventually consistent, per location).
• If the binding is absent or errors, a per-isolate token bucket with the same numbers (RATE_LIMIT_REQUESTS / RATE_LIMIT_PERIOD_SECONDS) is used instead.
• Exceeding it returns HTTP 429 with Retry-After; on /mcp the body is a JSON-RPC error (-32000), elsewhere the JSON error envelope. /health and OPTIONS are not metered. Responses carry x-ratelimit-limit / x-ratelimit-period.
• Free-plan ceiling to keep in mind: Workers Free allows 100,000 requests/day per account and 10 ms CPU per request (limits). A cold search costs ~1-3 ms CPU (parsing the ~135 KB index); warm requests well under 1 ms.

Local development & tests

npm install
npm run dev                  # wrangler dev on http://127.0.0.1:8787 (no Cloudflare login needed)
npm test                     # unit tests + 2x wrangler dev + E2E (REST, MCP both eras, rate limit) + MCP Inspector CLI
npm run test:unit            # pure unit tests (no network)
BASE=https://<deployed-host> npm run test:e2e   # E2E against any deployment
DATA_BASE_URL=http://127.0.0.1:8089 npm test   # point the local Workers at another copy of the site

The long-form E2E checks adapt to the data: with published items they fetch one of each type over REST and MCP; with none (all drafts) they check the empty listings and not-found paths. To exercise the full path before anything is published, build the site with drafts published (e.g. INCLUDE_DRAFTS=1 SITE_URL=http://127.0.0.1:8089 node scripts/build.mjs in the site repo), serve dist/ on that port, and run npm test with DATA_BASE_URL set.

scripts/test-local.sh starts the normal Worker on :8797 and a low-limit copy (--env ratelimit-test, 5 req / 10 s) on :8798, runs test/e2e.mjs, then checks the server with @modelcontextprotocol/inspector --cli in the default legacy era and pinned to the modern era (protocolEra: "modern" config).

Manual checks:

npx mcp-inspector --cli http://127.0.0.1:8787/mcp --transport http --method tools/list
npx mcp-inspector --cli http://127.0.0.1:8787/mcp --transport http --method tools/call \
  --tool-name search --tool-args-json '{"query":"browser automation","limit":3}'
curl -s http://127.0.0.1:8787/mcp -H 'content-type: application/json' \
  -H 'accept: application/json, text/event-stream' \
  -d '{"jsonrpc":"2.0","id":1,"method":"tools/call","params":{"name":"get_entry","arguments":{"id":"x402"}}}'

Connecting a client

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

JSON config (e.g. Claude Code's .mcp.json; Claude Code requires "type": "http" for remote servers):

{ "mcpServers": { "indexagentica": { "type": "http", "url": "https://mcp.indexagentica.com/mcp" } } }

Other clients use their own name for Streamable HTTP (Cline: "type": "streamableHttp"; some accept just "url").

Configuration (wrangler.toml [vars])

Var	Default	Meaning
DATA_BASE_URL	https://indexagentica.com	Where /api/index.json is fetched from
CACHE_TTL_SECONDS	600	In-memory / Cache API TTL
RATE_LIMIT_REQUESTS, RATE_LIMIT_PERIOD_SECONDS	120, 60	Documented limit + fallback bucket (keep in sync with [ratelimits.simple])
ALLOWED_ORIGINS	*	Comma-separated Origin allow-list for browser callers
PUBLIC_BASE_URL	request origin	Canonical base for links in GET /
CF_ACCOUNT_ID	(none)	Account for the Analytics Engine SQL API (/stats)
STATS_API_SINCE, STATS_BEACON_SINCE	2026-10-02T20:21:47Z, (deploy time)	Where MCP/REST and site-beacon counting start (shown as since in /stats)
HIT_ORIGINS	https://indexagentica.com,https://www.indexagentica.com	Origins allowed to POST /hit

Secret: CF_ANALYTICS_TOKEN (Account Analytics Read), set with wrangler secret put CF_ANALYTICS_TOKEN. Bindings: ANALYTICS and HITS (Analytics Engine), STATS_KV (KV), RATE_LIMITER; cron 30 0 * * *.

Deploy

See DEPLOY.md for the options for mcp.indexagentica.com and the exact Cloudflare/GoDaddy access needed. Short version:

export CLOUDFLARE_ACCOUNT_ID=...   # from the Cloudflare dashboard
export CLOUDFLARE_API_TOKEN=...    # custom token, permissions in DEPLOY.md
npm run deploy:dry                 # build only
npm run deploy                     # -> https://mcp.indexagentica.com (custom domain)
                                   #    + https://indexagentica-mcp.indexagentica.workers.dev
BASE=https://mcp.indexagentica.com npm run test:e2e

Layout

src/index.js      router, CORS, JSON errors, REST endpoints, rate-limit gate
src/mcp.js        stateless dual-era MCP JSON-RPC handler
src/tools.js      tool definitions (schemas) + implementations shared with REST
src/search.js     scoring / filtering
src/data.js       fetch + cache of /api/index.json
src/ratelimit.js  Workers rate limiting binding + in-isolate fallback
src/openapi.js    OpenAPI document for the REST API
src/analytics.js  per-request usage logging to Workers Analytics Engine (no-op without the binding)
src/ua.js         human (browser) vs agent User-Agent classification
src/hits.js       POST /hit: site beacon validation + logging (dataset indexagentica_hits)
src/stats.js      GET /stats: Analytics Engine SQL aggregation, KV daily rollup (cron), caching
test/             unit tests, E2E script, Inspector config
docs/             proposed copy for llms.txt, /agents and the directory listing

License: code MIT; directory content CC BY 4.0.

Registry metadata

• server.json: official MCP Registry entry (com.indexagentica/mcp, schema 2025-12-11), validated with mcp-publisher validate. Publishing uses HTTP domain auth against https://indexagentica.com/.well-known/mcp-registry-auth; it's a separate, manual step once the endpoint is live.
• glama.json: Glama ownership claim (maintainer Drudley).
• llms-install.md: install notes for agent-driven installers such as Cline.

License

MIT for the code. Directory content served by the tools is CC BY 4.0.