Agent Nexus

Measured conclusion: Alive, not deep-tested. L2 outcome: not_attempted.

Agent-native registry to discover APIs, MCP servers and CLIs, with live health checks.

Add to your agent

Copy this into your MCP client config:

{
  "mcpServers": {
    "Agent Nexus": {
      "url": "https://agentnexus.app/mcp",
      "transport": "streamable-http"
    }
  }
}

Measured tools (6)

• discover_capabilities read-only

  Call this first whenever a task needs an external service (email, payments, search, storage, LLMs, data...) or when a service you use is failing. Maps a plain-language goal (e.g. 'send a transactional email') to callable APIs, MCP servers or CLIs. Returns matches[] with slug, endpoint, auth, formats, rate limit, pricing and a 0-100 reliability score; if nothing fits, coverage='none' and matches[] lists reliable starting points. Rate limits: 100 calls/day anonymous, 1,000/day with a free key, 50,000/day on Agent Pro. For a known keyword or slug, use search_registry.

  Parameters:

  • need (required) — string — What the agent is trying to accomplish, in plain language. 3-300 characters, required.
  • limit — integer — Maximum number of matching interfaces to return, 1-20. Default 5.
  • category — string — Restrict to one interface layer ('api', 'mcp' or 'cli' — see list_categories). Default: omitted, searches all three.
  • min_reliability — integer — Drop interfaces scoring below this 0-100 reliability value. Default 0 (no filter).

  Hints: read-only yes · destructive no · idempotent yes · open-world no

• search_registry read-only

  Keyword lookup in the Agent Nexus registry when you already know what to look for: a product name, vendor, slug or endpoint fragment, optionally narrowed to one category. Matches literal text only — it does not interpret a goal. To go from a plain-language need to a callable interface, use discover_capabilities instead; to walk the whole catalogue in order use list_entries, and for the full record of one known slug use get_entry. Read-only and side-effect free. Returns {count, results[]} where each result is a summary entry record (slug, name, category, summary, endpoint, trust fields). Results are ordered alphabetically by name, not by relevance; there is no pagination beyond the limit parameter — raise limit (max 50) or narrow the query to see more. An empty results[] when nothing matches is a valid answer, not an error.

  Parameters:

  • limit — integer — Upper bound on entries returned, 1-50, default 10. Results are ordered by name, not by relevance, so a small limit on a broad keyword can hide better matches — raise it or use discover_capabilities when you are ranking candidates.
  • query — string — Literal substring, max 120 chars, matched case-insensitively against name, summary, endpoint and slug — a product name ('resend'), a vendor, a slug fragment or a host ('api.stripe.com'). Single terms work best: the whole string is matched as one substring, so 'send email' finds nothing unless those words appear together. The characters % , ( ) are stripped. An empty query (the default) returns the first entries in name order, which is a browse, not a search.
  • category — string — Optional filter, exactly one of 'api', 'mcp' or 'cli' (see list_categories). Combined with query as AND. Omit to search all three layers.

  Hints: read-only yes · destructive no · idempotent yes · open-world no

• get_entry read-only

  Before calling a known service, check it is live right now and get its exact contract. Fetches the full record of ONE approved registry entry whose exact slug you already have, e.g. from a previous discover_capabilities, search_registry or list_entries result. Read-only and idempotent: the same slug always returns the same entry until its health probe changes. Returns {entry} with endpoint, auth mode and parameters, input/output formats, rate limit, pricing, capabilities, docs URL, invocation example and the latest 6-hourly health probe — the detail level the listing tools omit. This is the single-record lookup: it takes no filters and no paging. If you do not have a slug, do not guess one — use search_registry for a keyword or discover_capabilities for a plain-language need; to walk the whole catalogue use list_entries. An unknown or unapproved slug is an error, not an empty result.

  Parameters:

  • slug (required) — string — Exact lowercase slug of one entry, 1-80 chars, as returned in the 'slug' field of any other tool, e.g. 'stripe-api' or 'github-mcp'. Case-sensitive, no URL and no display name; only entries with status 'approved' resolve.

  Hints: read-only yes · destructive no · idempotent yes · open-world no

• list_categories read-only

  Return the fixed taxonomy of Agent Nexus: the three interface layers it indexes ('api', 'mcp', 'cli'), each with a label, a one-line definition and its live count of approved entries. Read-only, idempotent and parameterless — call it once to learn the exact values accepted by the 'category' argument of search_registry, list_entries and discover_capabilities, and to size the catalogue before paging. It never returns entries themselves: use list_entries to enumerate a layer, search_registry for a keyword, discover_capabilities for a plain-language need.

  Hints: read-only yes · destructive no · idempotent yes · open-world no

• list_entries read-only

  Enumerate the whole approved catalogue in deterministic slug order, page by page — use this when you want everything (mirroring, auditing, building your own index), not when you are looking for something specific. Read-only and idempotent. Returns {total, page, per_page, pages, results[]}: read 'pages' from the first response and increment 'page' until you reach it; 'total' and 'pages' reflect the 'category' filter when one is set, so keep the filter identical across pages or the paging shifts. Entries come back in summary form; call get_entry with a slug for the full record. For a keyword use search_registry, for a plain-language need use discover_capabilities, and for the accepted category values call list_categories. Bulk mirror alternative: GET https://agentnexus.app/api/public/entries.ndjson streams the full catalogue in one request.

  Parameters:

  • page — integer — 1-based page index. Start at 1 and increment until it equals the 'pages' value returned in the response; a page beyond the last one returns an empty results[] rather than an error.
  • category — string — Optional filter, exactly one of 'api', 'mcp' or 'cli' (see list_categories). Omit to page through all three layers. When set, 'total' and 'pages' count only that layer.
  • per_page — integer — How many entries to return in this page, 1-50, default 25. Changing it between calls changes 'pages' and re-slices the catalogue, so keep it constant while paging.

  Hints: read-only yes · destructive no · idempotent yes · open-world no

• submit_entry

  Register a new interface (HTTP API, MCP server or CLI) in the Agent Nexus catalogue. Callers authenticate either as a signed-in member or with a free agent key (POST https://agentnexus.app/api/public/keys), which allows one submission per key and per source address per 24 hours. This is a write: it creates a pending row, it does NOT publish anything — every submission is reviewed by a human before it becomes discoverable, so nothing you send here is visible to other agents until it is approved. Nothing is overwritten or deleted, and re-submitting the same name creates a second pending row rather than updating the first. Five fields are required (name, category, summary, endpoint, auth_mode); everything else is optional but directly decides whether the entry is approved and how well it ranks: capabilities[] is what other agents are matched against, so list concrete verbs, and docs_url plus invocation_example are what a reviewer checks first. Rate limited to 20 submissions per hour for members and 1 per 24 hours per agent key and per source address, and the endpoint must answer a live health probe to keep a reliability score. Returns {slug, status}; poll GET https://agentnexus.app/api/public/submission?slug=<slug> for the decision, or pass contact_email to be emailed instead. Use list_my_submissions to review what you already submitted; use search_registry first to check the interface is not already listed.

  Parameters:

  • name (required) — string — Public product name as its vendor spells it, 1-80 chars, e.g. 'Resend' or 'GitHub MCP Server'. Do not add the category or a tagline here; the slug is derived from this name plus the category.
  • category (required) — string — Which layer this interface belongs to: 'api' for an HTTP contract called directly, 'mcp' for a Model Context Protocol tool server, 'cli' for a command-line surface. Decides how endpoint is interpreted (URL vs command).
  • summary (required) — string — One line an agent can rank on: what the interface does, 10-300 chars. State the capability, not the marketing (e.g. 'Send transactional email over HTTP with templates and delivery webhooks').
  • endpoint (required) — string — How the interface is actually reached, max 500 chars. For category 'api' the base URL (https://api.example.com/v1); for 'mcp' the server URL (https://example.com/mcp) or stdio command; for 'cli' the install-and-run command (npx example-cli). Must be reachable: it is probed daily and a dead endpoint loses its reliability score.
  • auth_mode (required) — string — How a caller authenticates, in a few words: 'none', 'Bearer API key', 'API key in query', 'OAuth 2.1', 'Basic auth'. Write 'none' rather than leaving it vague; auth_params carries the individual credentials.
  • tags — array — Up to 8 short domain labels for browsing, e.g. ['email','messaging']. Domains, not actions — actions belong in capabilities[].
  • pricing — string — Cost in one short phrase, e.g. 'Free', 'Free tier then $20/month', 'Usage-based, $0.001/call'. Agents filter on this, so be concrete.
  • docs_url — string — Absolute https URL of the developer documentation (not the marketing home page). Omit if none exists; submissions without it are approved more slowly.
  • rate_limit — string — Published quota in the vendor's own words, e.g. '100 requests/minute', '10k calls/month on the free tier'. Leave empty rather than guessing.
  • auth_params — array — Up to 10 individual credentials the caller must supply, each {name, location, required}. Leave empty when auth_mode is 'none'. Never include credential values here, only their names.
  • description — string — Optional long form, max 4000 chars: what the interface does well, notable limits, quirks an agent should know before calling. Plain text; no HTML.
  • capabilities — array — Up to 12 lowercase hyphenated verbs an agent's need is matched against, e.g. ['send-email','list-templates','verify-address']. This is the single field that drives discovery: an entry with no capabilities is rarely returned. One action per item, 2-40 chars, no sentences.
  • input_format — string — MIME type or shape the interface accepts, e.g. 'application/json', 'multipart/form-data', 'command-line flags'. Empty string when not applicable.
  • contact_email — string — Optional. Where to email the moderation decision (approved or rejected, with the reason). Never published, never shared.
  • output_format — string — MIME type or shape the interface returns, e.g. 'application/json', 'text/csv', 'stdout text'. Empty string when not applicable.
  • invocation_example — string — One copy-pasteable call that works: a curl command, a JSON-RPC body or a CLI line, max 1000 chars. Never include a real credential — use a placeholder such as $API_KEY. This is what reviewers check first.

  Hints: read-only no · destructive no · idempotent not declared · open-world yes

Repository

Measured by MCPYP probing. Untested fields are omitted, never estimated. Listing is always free; MCPYP never proxies calls or stores user tokens.