# MCP Developer > Use when building, testing, debugging, or reviewing Model Context Protocol servers, clients, transports, tools, resources, prompts, and agent host configuration. - Skill: `tomevault-io/mcp-developer` (Agent Skill, multi-file: 2 files) - Install (CLI): `npx skillmds@latest add tomevault-io/mcp-developer` - Raw SKILL.md: https://api.skillmd.com/api/skills/tomevault-io/mcp-developer/raw - Safety review: pending (external: skill-scanner PASS, skillspector PASS) - Works with: Claude Code, Claude.ai, OpenAI Codex - Category: AI & ML - Author: tomevault-io (https://skillmd.com/u/tomevault-io) - Updated: 2026-09-17 - Page: https://skillmd.com/skills/tomevault-io/mcp-developer --- # MCP Developer Use this skill when the work involves MCP protocol behavior, cross-SDK interop, server/client debugging, or host configuration. ## Workflow 1. Identify the transport first: stdio, Streamable HTTP, SSE, or a host-specific adapter. 2. Preserve wire-level MCP semantics. Keep JSON-RPC ids, method names, capability flags, metadata, and error codes in their original spec-compatible shape. 3. Check advertised capabilities before calling capability-specific methods. 4. Reproduce with a protocol-level tool before editing app code: - `mcp_dart inspect-server --json -- ...` - Configure a client/agent host to launch `mcp_dart inspect-client --report /tmp/mcp-client-report.json` - Configure a client/agent host to launch `mcp_dart trace --report /tmp/mcp-trace.json -- ...` - `mcp_dart list-tools -- ...` - `mcp_dart call-tool --json-args '{"key":"value"}' -- ...` - `mcp_dart inspect --url http://localhost:3000/mcp` 5. Use `--probe-config` with `inspect-server` when a server needs real tool arguments, resource URIs, prompt arguments, completion values, or task behavior. Keep destructive app actions out of default probes. 6. Treat `inspect-server`, `inspect-client`, and `trace` as the live debugging workflow. They return protocol checks or traffic evidence for real targets; there is no separate live validation command to prefer. 7. If changing this Dart SDK/CLI package itself, also run `mcp_dart conformance --suite all --json` for the built-in protocol regression fixtures. 8. For cross-language issues, test at least one non-Dart peer. Prefer the official TypeScript or Python MCP SDK when a reproduction can be made small, and use published servers such as filesystem/time when the bug depends on real package behavior. 9. When changing protocol behavior, add regression coverage for the raw wire shape or interop edge case, not only a convenience API test. ## Host Configuration Checks - Confirm the host launches the exact command and arguments you tested manually. - Keep secrets in environment variables or host secret stores, not generated config files. - Avoid printing diagnostic text to stdout for stdio servers; stdout is reserved for JSON-RPC frames. - Use `inspect-client --report ` for agent hosts or clients that need a disposable MCP server to connect to. - Record the MCP protocol version, SDK/package version, and transport in issue notes. ## Release And Install Checks - If the CLI is needed on machines without Dart, use the GitHub release binary. - Use `mcp_dart update` for normal upgrades. For manual installs, rerun the installer command against the same install directory. - Before recommending a release, verify `dart analyze`, focused tests, and any TypeScript/Python interop smoke tests affected by the change. --- > Source: [leehack/mcp_dart](https://github.com/leehack/mcp_dart) — distributed by [TomeVault](https://tomevault.io).