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Tooling protocol

Negotiate editor and MCP clients over bounded JSON-RPC without granting ambient project or network authority.

In this guideTooling protocol

Getting started Project structure CLI reference Developer loop Incremental builds Routing and pages Rust views Events and folds Schemas and snapshots Hyphae verified sync Typed content Browser runtime DOM ownership Native runtime preview Portable deployment Full-stack beta OpenSDK preview Components and languages Browser framework conformance Tooling protocol Compatibility and deprecation Adaptive assets Artifact trust Release trust Performance evidence Errors and diagnostics Voluntary telemetry Build and deploy Crates and API Licensing and policy

One bounded tooling plane

The OpenSDK tooling host uses newline-delimited JSON-RPC 2.0 over standard input and output. Editors negotiate through pliego/handshake; the reference MCP adapter exposes the same capability handshake after completing the MCP 2025-11-25 initialization lifecycle.

OpenSDK: 0.4.0-beta.1
JSON-RPC: 2.0 over bounded newline-delimited messages
MCP: 2025-11-25 reference client surface

Negotiate before diagnostics

shell

cargo run -p pliego-cli --locked -- sdk tooling-host \
  --protocol pliego \
  --feature diagnostic-links

The native handshake must include protocolVersion 0.4.0-beta.1. Missing or incompatible versions fail before any diagnostic or project method becomes available.

MCP is a client, not a privilege

shell

cargo run -p pliego-cli --locked -- sdk tooling-host \
  --protocol mcp \
  --feature diagnostic-links
npm run check:opensdk:tooling

The MCP client receives no implicit filesystem root, network access, sampling, elicitation, or project capability. Its reference tool accepts only the empty arguments object declared by its schema and cannot bypass OpenSDK admission policy.

Fail with structured boundaries

The host accepts at most 10,000 requests per process and 1 MiB per JSON line. Invalid JSON-RPC versions, unknown fields, unsupported MCP versions, pre-initialization calls, unknown methods, and unknown tools return structured errors; notifications produce no response.

Complete tooling protocol