Protocol constants

type: module path: "@root/src/PuduLangMcp/Constants/Protocol.pudu" fidelity: Active grammar: "[[grammar/pudu]]" depth_score: 0.2 depth_status: SHALLOW coupling: 0 interface_stability: 0.9 tags: [module, shallow] aliases: [Protocol Constants]

Purpose

Every literal the MCP and JSON-RPC specifications fix: protocol versions, metadata keys, error codes, and result fields. No other module spells these.

Interface

Signatures

export const MODERN_VERSION: Str            // "2026-07-28"
export const LEGACY_VERSIONS: Array[Str]    // newest first
export const LATEST_LEGACY_VERSION: Str
export const JSONRPC_VERSION: Str
export const META_KEY: Str                  // "_meta"
export const META_PROTOCOL_VERSION: Str
export const META_CLIENT_CAPABILITIES: Str
export const META_SERVER_INFO: Str
export const PARSE_ERROR: Int               // -32700
export const INVALID_REQUEST: Int           // -32600
export const METHOD_NOT_FOUND: Int          // -32601
export const INVALID_PARAMS: Int            // -32602
export const INTERNAL_ERROR: Int            // -32603
export const UNSUPPORTED_PROTOCOL_VERSION: Int   // -32022
export const RESULT_COMPLETE: Str           // "complete"
export const CACHE_PUBLIC: Str
export const CACHE_PRIVATE: Str
export fn supportedVersions() -> Array[Str] // modern first, then legacy
export fn isLegacyVersion(version: Str) -> Bool

Linkage

• Requires: std only.
• Consumed by: [[src/PuduLangMcp/Errors/RpcError]], [[src/PuduLangMcp/Domain/Protocol/Negotiation]], [[src/PuduLangMcp/Domain/Rpc/Reply]].

Algorithm

Constants only; isLegacyVersion is membership in LEGACY_VERSIONS.

Negative Logic (Prohibited Paths)

• No code emits a code in -32000..-32019 or an undefined code in -32020..-32099.
• -32002 (legacy resource-not-found) is never emitted.

Edge Cases

• A version string differing only in case is a different, unsupported version.

Depth

DEPTH 0.2 (SHALLOW). A vocabulary; its value is that nothing else spells these literals.

Grill Log

• Q: Keep a metadata key that no request reads? A: No; the protocol accepts client info without naming that key in server logic. _Rejected:_ an unused exported constant.
• Q: Which legacy versions? A: 2025-11-25, 2025-06-18, 2025-03-26, 2024-11-05. _Rationale:_ the method and result shapes this server uses are unchanged across them. _Rejected:_ only 2025-11-25, which strands older clients for no gain.

Referenced by

[[src/PuduLangMcp/Constants/_MOC]]