Module rpc 

JSON-RPC 2.0 / MCP tools/call parsing. Total: never panics on arbitrary bytes (property-tested), returns typed errors for every malformed shape.

Structs

ToolCallRequest

A parsed MCP tool-call request.

Enums

RpcError

Parse failures.

Constants

MAX_JSON_DEPTH

Depth bound applied post-parse (deeply nested JSON as a DoS vector).

MAX_PAYLOAD_BYTES

Hard byte bound applied before parsing (attacker-controlled input).

Functions

authorization_error

Build the JSON-RPC error response for a blocked call (the “immediate authorization error back to the agent loop” from the brief).

denial_error

authorization_error plus the machine-readable denial code in error.data.code, so an agent can branch on the code without parsing the reason text.

depth_of

Compute the maximum nesting depth of a JSON value. Exposed so callers outside this crate (chat-completions ingress and any admin body parser) can apply the same trust-boundary depth cap without duplicating logic.

detectable_error_id

Recover the request id for an error response, per JSON-RPC 2.0 §5: the response id MUST echo the request’s when it is detectable, and be null only “if there was an error in detecting the id” (parse error / invalid request). RpcError::NotToolCall and RpcError::BadParams both mean the envelope parsed as a well-formed JSON-RPC 2.0 object, so the id IS detectable — replying null broke client correlation (a pending initialize call hung until timeout because its error response carried id: null). Parse-class failures (invalid JSON, duplicate keys, oversize, non-2.0 envelope) keep null: the id is absent, ambiguous, or untrustworthy there.

parse_tool_call

Parse raw bytes as an MCP tools/call.

protocol_error

JSON-RPC 2.0 reserves -32700 (parse error), -32600 (invalid request), and -32602 (invalid params) for requests that never reached application logic. Reporting those as -32001 “blocked by policy” (with HTTP 403) falsely told clients an authorization decision was made about a request that never parsed.

refuse_duplicate_json_keys

The general-purpose duplicate-key rejection primitive, exposed for callers outside this crate (chat completions ingress, admin body parsers) that want the same trust-boundary “refuse ambiguous JSON” semantics without pulling in RpcError.