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SimpleFunctions has several tool catalogs. They are not interchangeable.
  • Use GET /api/contracts/tools for strict SDK and Agent SDK contract truth.
  • Use sf describe --all --json for the installed local CLI command manifest.
  • Use GET /api/tools for the broad hosted HTTP compatibility inventory.
  • Use MCP only as an adapter for MCP-compatible hosts.
/api/tools is not the SDK/Agent contract manifest. It can include broad compatibility names such as get_world_state; SDK and Agent SDK code should use canonical dotted names such as world.read from /api/contracts/tools.

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Strict contract manifest

GET /api/contracts/tools
This is the canonical SDK/Agent tool universe. See Contract tools for schema version, access.anonymousAllowed, sideEffect, costEffect, Agent callability, SDK mapping, and replay metadata.

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Local CLI catalog

sf describe --all --json          # full installed command manifest
sf tools --json                   # HTTP catalog wrapped in CLI envelope
sf tools search "<task>" --json   # search by task / option / tag
sf tools plan "<task>" --json     # plan a command sequence
sf skills list --json             # discover skills locally
For agents running on a user machine, the CLI manifest is the canonical local command surface. It reflects the installed version, local auth, local-only commands, command policy metadata, and JSON capability flags. It is not the SDK/Agent package contract. See Tool manifest.

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HTTP tool catalog

GET /api/tools
Auth: none. Returns the broad hosted HTTP tool catalog used by remote integrations. Two tiers — public (no auth required) and authenticated (sf_live_...): 
curl "https://simplefunctions.dev/api/tools" | jq '.tools.public | length, .tools.authenticated | length'
Each tool record has name, description, endpoint (when there is a 1:1 HTTP route), parameters, auth, returns, and an example URL. This is not a byte-for-byte mirror of sf describe --all --json, and it is not the strict SDK/Agent manifest. Use /api/tools for the broad remote HTTP compatibility surface. Use sf describe --all --json for the installed CLI command catalog and its command-level policy metadata. Use MCP tools reference only for the MCP adapter inventory and input schemas. 
# all public tool names
curl -s "https://simplefunctions.dev/api/tools" \
  | jq -r '.tools.public[] | "\(.name)\t\(.endpoint)"'

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Skill catalog

GET /api/skills
Auth: none. Returns the bundled skill catalog. A skill is a reusable agent capability — a markdown bundle with a description, a trigger phrase, declared tools, and a prompt body. This endpoint is the network-side discovery view; user-authored skills live behind /api/skill*. 
{
  "skills": [
    {
      "name": "fed-watch",
      "trigger": "watch the Fed",
      "description": "Daily Fed-day workflow — check FOMC calendar, inspect rate-cut markets, summarise edges.",
      "category": "macro",
      "tags": ["fed", "rates"],
      "toolsUsed": ["get_world_state", "inspect_ticker", "get_calendar"],
      "estimatedTime": "30s",
      "prompt": "..."
    }
  ]
}
User-owned skills (create / fork / publish / run) live under /api/skill — see Skills.

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Prompt context

GET /api/prompt
Auth: required. Returns the SimpleFunctions prompt / runtime context for the current user — system prompt, active thesis hints, available tools, and recent activity, shaped for an agent that’s about to start a turn. 
curl -H "Authorization: Bearer $SF_API_KEY" \
  "https://simplefunctions.dev/api/prompt"

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MCP adapter

GET  /api/mcp/{transport}
POST /api/mcp/{transport}
Auth: none for tool discovery and public tools. Bearer sf_live_... to access authenticated tools (thesis, intents, portfolio, …). The MCP transport exposes SimpleFunctions tools to MCP-compatible clients (Claude Code, Cursor, Cline, …). Treat it as an adapter over the CLI/API product surface. See MCP server for client wire-up and MCP tools reference for the adapter tool list and input schemas. One-line client setup: 
claude mcp add simplefunctions --url https://simplefunctions.dev/api/mcp/mcp

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Voice — text-to-speech (TTS)

POST /api/proxy/tts
Auth: required (Authorization: Bearer sf_live_...). Body (JSON):
FieldTypeRequiredDefaultNotes
textstringyes—1 – 5000 chars.
voiceIdstringoptionalprofessional news anchor voiceCartesia voice id.
speednumberoptionalimplementation defaultSpeech rate.
languagestringoptionalenBCP-47 language tag.
Response: audio/mpeg binary stream (MP3). Errors
StatusBodyCause
400Invalid JSON bodyBody is not JSON.
400text required (string, min 1 char)Empty text.
400text too long (max 5000 chars)Over the limit.
401unauthorizedNo / invalid auth.
503TTS proxy not configuredServer has no Cartesia key configured.
curl -X POST -H "Authorization: Bearer $SF_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{"text":"Fed cuts in December","speed":1.0}' \
  "https://simplefunctions.dev/api/proxy/tts" \
  --output out.mp3

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Voice — speech-to-text (STT)

POST /api/proxy/stt
Auth: required. Body: multipart/form-data with field audio (or file). Max 10 MB. Response 200 
{
  "text": "Fed cuts in December",
  "duration": 1.84,
  "words": [
    { "text": "Fed", "start": 0.10, "end": 0.32 },
    { "text": "cuts", "start": 0.34, "end": 0.62 }
  ]
}
Errors
StatusBodyCause
400Expected multipart/form-data with "audio" fieldMissing form field.
400"audio" file field requiredField empty or wrong type.
400Audio file too large (max 10MB)Over the size limit.
401unauthorizedNo / invalid auth.
503STT proxy not configuredServer has no Cartesia key configured.
curl -X POST -H "Authorization: Bearer $SF_API_KEY" \
  -F "audio=@clip.wav" \
  "https://simplefunctions.dev/api/proxy/stt"
The sf agent voice mode uses these endpoints internally; you only need to call them directly when wiring SimpleFunctions tools into another voice agent.

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See also

Tool manifest

Local discovery via sf describe --all --json.

Skills

User-owned skill CRUD, fork, publish.

MCP server

Adapter for Claude Code, Cursor, Cline.

MCP tools reference

MCP adapter inventory and input schemas.