indexagentica-mcp
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 |
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 theMCP-Protocol-Version,Mcp-Method(and fortools/call,Mcp-Name, base64 sentinel supported) headers. The server validates headers against the body (-32020 HeaderMismatch), rejects unknown versions with-32022+supportedlist, implementsserver/discover, returnsresultType: "complete",serverInfoin result_meta, andttlMs/cacheScopecaching hints ontools/listandserver/discover. Unknown methods -> HTTP 404 +-32601. - 2025-11-25 / 2025-06-18 / 2025-03-26 ("legacy"):
initializeis answered (version negotiated, falling back to 2025-11-25),notifications/initialized-> 202,ping,tools/list,tools/call; 2025-03-26 batches are accepted. NoMcp-Session-Idis ever issued, so every request is independent and any Worker isolate can serve it. - Responses are always
application/json(never SSE).Originis checked againstALLOWED_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 |
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) |
blob8 | traffic: internal / outside (empty before 2026-10-12) |
blob9 | internal rule: header, ua, ip |
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"}.
Every window counts outside traffic only and adds: site.downloads.by_skill,
site.outbound_clicks_by_entry, mcp.top_clients (self-reported MCP client names, lowercased and
stripped to [a-z0-9._ -], top 10, only names seen ≥ 3 times), top_user_agent_families (bot name,
browser, headless-chrome or first product token; top 10, ≥ 3) and internal_excluded (what was left
out, by rule). KV days carry a rollup version (v); days from an older version are recomputed while the
raw data is still retained, so rule changes apply retroactively. The lazy catch-up recomputes at most 2
days per /stats call and the cron 5 per run (each day is ~7 SQL subrequests; Workers Free allows 50).
Internal traffic
Our own tests, monitors and agents are logged but excluded from /stats. A request or beacon is
internal if any rule matches (src/internal.js):
| Rule | Match |
|---|---|
header | X-Indexagentica-Internal: 1 (allowed in CORS; test/e2e.mjs sends it on every request) |
ua | User-Agent contains indexagentica (our clients use indexagentica-<agent>/1) |
ip | client IP inside a CIDR listed in the optional secret INTERNAL_IPS (comma-separated, IPv4/IPv6). Unset: our shared box egresses through rotating addresses in a shared relay range, so an IP rule would also drop strangers |
Rows logged before the flag existed (2026-10-12) are matched retroactively in SQL by the signature of
our own sessions (API_RETRO / HITS_RETRO in src/stats.js): API rows whose MCP client name is
e2e (our test suite), or from the US with a curl/node/python/headless-Chrome User-Agent inside the
documented launch and verification windows (2026-10-02 20:15–20:45 and 2026-10-03 04:55–05:50 UTC),
and site beacons from the US between 05:00 and 05:50 UTC on 2026-10-03. This is best effort: internal
sessions that looked like outside traffic may still be counted, and outside requests with the same
generic clients inside those windows are excluded.
How our own agents should call the server:
curl -H 'X-Indexagentica-Internal: 1' -A 'indexagentica-steward/1' https://mcp.indexagentica.com/stats
Rate limiting
- Default: 120 requests / 60 s per client IP, per Cloudflare location, via the
Workers Rate Limiting binding
(
[[ratelimits]]inwrangler.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/mcpthe body is a JSON-RPC error (-32000), elsewhere the JSON error envelope./healthandOPTIONSare not metered. Responses carryx-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) |
INTERNAL_IPS (secret, optional) | (none) | Comma-separated CIDRs whose requests count as internal traffic |
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
src/internal.js internal-traffic rules (header, UA, optional IP ranges)
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 withmcp-publisher validate. Publishing uses HTTP domain auth againsthttps://indexagentica.com/.well-known/mcp-registry-auth; it's a separate, manual step once the endpoint is live.glama.json: Glama ownership claim (maintainerDrudley).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.