Use these definitions when reading ToolRouter documentation, interpreting schemas, or deciding how an agent should call the platform.
Agent
Software that selects and calls tools to complete a user-directed task. An agent remains responsible for reasoning, permissions, and deciding whether an external action is necessary.
Tool
A named capability group in the ToolRouter catalog, such as Web Search or SEO Analysis. A tool contains one or more callable skills.
Skill
A single callable operation within a tool. Every skill publishes a name, description, JSON input schema, examples, and a response contract.
MCP
Model Context Protocol, the agent-native transport ToolRouter uses for discovery and tool calls. ToolRouter supports remote Streamable HTTP at https://api.toolrouter.com/mcp and a local stdio package named toolrouter-mcp.
REST API
The versioned HTTP interface under https://api.toolrouter.com/v1. REST is the best fit for backend applications and automations that need direct JSON requests and responses.
OpenAPI
The machine-readable REST contract at https://toolrouter.com/openapi.json. It defines operations, request bodies, response schemas, error objects, and relevant headers.
Provider
An upstream service that performs some tool work. ToolRouter normalizes provider authentication and responses, and some skills can route across more than one provider.
BYOK
Bring your own key. A caller supplies its own upstream provider credential while still using ToolRouter discovery, schemas, execution, and response normalization.
API key
A ToolRouter credential used to authenticate REST, CLI, or MCP calls. Keys are secrets and must not be committed, logged, or placed in public client code.
Credits
Prepaid ToolRouter balance used for paid skills. Free skills do not consume paid credits. A response may include usage and cost metadata for the completed call.
JSON Schema
The structured definition of accepted inputs or returned fields. Agents should read the live schema instead of guessing parameter names or types.
Typed error
A JSON failure object with a stable machine-readable code and a human-readable message. Agents should branch on the code and use published resolution guidance when present.
Rate limit
The request quota advertised in RateLimit and RateLimit-Policy response fields. A 429 response includes Retry-After when the caller should wait before retrying.
Asset
A generated or uploaded file returned through ToolRouter's asset delivery system. Responses can include an asset identifier, download URL, content type, and expiry or metadata fields.
MCP server card
The discovery document at /.well-known/mcp.json. It identifies ToolRouter's MCP server, version, remote transport, and npm package.
llms.txt
The curated Markdown index at /llms.txt. It tells agents what ToolRouter is, when to use it, and where to find clean documentation and machine-readable contracts.
Agent Skill
A focused instruction file advertised through /.well-known/agent-skills/. It explains how an agent should perform a specific ToolRouter workflow and what inputs or constraints apply.
Deprecation and sunset
Deprecation means an API surface remains available but should no longer be chosen for new integrations. Sunset is the announced date after which that surface may stop responding. See the API lifecycle policy.