Expand description
JSON-RPC 2.0 (https://www.jsonrpc.org/specification) and the parts of MCP 2025-06-18 Sioul answers: the handshake (“Lifecycle”), ping, tools, and a few resources made by the same tools. One message in, at most one out; the transport only carries them.
Structs§
- Failure
- A request that failed: its JSON-RPC code, and what to say.
- Resource 🔒
- A resource always there, made by a tool with fixed arguments.
- Server
- One connection’s server: where the configuration is, the language, and who asked.
- Template 🔒
- Resources named by an address: a note by its path, a message by its Message-ID.
Constants§
- INSTRUCTIONS 🔒
- What the agent is told once, at the handshake, before any tool.
- INTERNAL_
ERROR 🔒 - INVALID_
PARAMS 🔒 - INVALID_
REQUEST 🔒 - METHOD_
NOT_ 🔒FOUND - PARSE_
ERROR 🔒 - PROTOCOL_
VERSION - The revision of MCP this server follows.
- RESOURCES 🔒
- RESOURCE_
NOT_ 🔒FOUND - SUPPORTED 🔒
- The revisions a client may ask for: tools and resources are the same in each, and what is newer (titles, structured content) older clients leave aside.
- TEMPLATES 🔒
Functions§
- failure 🔒
- tool_
result 🔒 - A tool’s answer as MCP’s CallToolResult: its text, its data, and whether it failed. A failure is said in the result, not as a protocol error, so the agent can correct itself.
- unreadable
- A line the transport could not take (too long, not UTF-8): JSON-RPC’s parse error, as its id cannot be read.