404.directory: one-call official docs search and a read-only Agent trust gateway

[MM-sheng]

404.directory v0.8.0 is live in the Official MCP Registry as io.github.MM-sheng/404-directory.

The problem it targets is tool selection before execution: an Agent should be able to find a useful tool, inspect its trust evidence, and call only an approved read-only operation without wiring a different server for every task.

The public remote MCP endpoint currently exposes 12 tools with no account or API key. The lowest-friction entry point is search_official_docs, which searches current first-party documentation from OpenAI, Microsoft Learn, AWS, and Cloudflare in one call and returns source URLs.

A useful first prompt is:

Use 404.directory to find the current official documentation for background tasks in the OpenAI Responses API. Cite the first-party source and do not rely on third-party tutorials.

For broader tool discovery, the Agent can use:

• search_tools and recommend_tools for capability discovery
• get_trust_score and compare_tools before selection
• inspect_tool_server to retrieve the current approved schemas for a curated remote MCP server
• invoke_registered_tool to execute one approved read-only operation

Safety boundaries are deliberately narrow: registered remote calls are allowlisted and read-only, remote descriptions/results are treated as untrusted data, and callers are warned not to send credentials, private code, personal data, or secrets.

Install and verify:

• Generated one-click VS Code / GitHub Copilot Agent install, plus Codex, Cursor, Claude Code, and SDK configurations: https://404.directory/connect?source=mcp-registry-showcase
• MCP endpoint: https://404.directory/mcp
• Health and current tool list: https://404.directory/health
• Machine-readable tool docs: https://404.directory/docs.md
• Autonomous Agent discovery record: https://integrations.sh/404.directory/
• Owner-declared integration map: https://404.directory/.well-known/integrations.json
• RFC 9727 API Catalog: https://404.directory/.well-known/api-catalog
• Official Registry name: io.github.MM-sheng/404-directory
• Source: https://github.com/MM-sheng/404-directory

Each generated install configuration includes a fresh, random, non-personal X-404-Agent-ID. The raw value is never persisted; only an irreversible HMAC digest is stored after a successful tool execution. Prompts, tool arguments, results, and raw identifiers are excluded from product analytics. The de-duplicated public adoption metric is visible at https://404.directory/v1/metrics/agents.

I would especially value feedback on two questions: whether search_official_docs is specific enough for reliable automatic tool selection, and what additional evidence an Agent should require before invoking a third-party read-only tool through a trust gateway.

[MM-sheng]

v0.8.1 adds an installable cross-client Agent Skill so Agents can move from registry discovery to a useful first call without hand-written prompting.

Install in Codex, Claude Code, Cursor, Cline, and other Agent Skills clients:

npx skills add MM-sheng/404-directory --skill use-404-directory -g -y

Skill page: https://www.skills.sh/mm-sheng/404-directory/use-404-directory

The Skill routes official technical questions to search_official_docs, deployment claims to evidence-based verify_web, and catalog tasks through trust comparison plus live schema inspection before any approved read-only invocation. It also explicitly rejects traffic-only calls and requires a useful non-error result before reporting success.

Official Registry v0.8.1: https://registry.modelcontextprotocol.io/v0.1/servers/io.github.MM-sheng%2F404-directory/versions/latest

[MM-sheng]

Update: v0.9.0 now turns registry discovery into an actual Agent activation path.

• One-click Cursor and VS Code/Copilot setup
• Claude Code plugin and direct MCP commands
• Codex configuration
• A concrete first-use prompt for search_official_docs
• Machine-readable setup

The same Registry server remains packaged as a portable Agent Plugins 1.0 plugin plus a lightweight Claude marketplace package. The package uses a dependency-free local bridge to generate and preserve one random non-personal ID per plugin installation. The raw ID stays local; 404.directory stores only an HMAC digest after a successful tool execution. Prompts, arguments, results, probes, anonymous calls, self-tests, and duplicates are excluded from the public adoption target.

Claude Code direct install:

/plugin marketplace add MM-sheng/404-directory
/plugin install 404-directory@404-directory

GitHub Copilot's external-plugin intake passed its automated gates and is awaiting maintainer review: github/awesome-copilot#2767

Release: https://github.com/MM-sheng/404-directory/releases/tag/v0.9.0