404.directory is an MCP server with 16 tools an agent can call, among them compare_tools, evaluate_prediction_market, evaluate_tool_risk. It answers at https://404.directory/mcp over streamable HTTP, and it listed its tools to an anonymous client, so no sign-in was needed for that. Our probes reached it 5 of 6 times since 11 September 2026; the last check, on 20 October 2026, succeeded.
Risk preflight for AI Agent tool actions and Polymarket settlement and execution checks.
Description as the publisher wrote it.
| Tool | What it does |
|---|---|
compare_tools | Compare up to 5 ecosystem tools side-by-side (capabilities, trust dimensions, usage). Inputs: ids_or_slugs |
evaluate_prediction_market | Evaluate one specific Polymarket market before an AI Agent observes or contemplates buying or selling a Yes/No position. Use immediately before a decision when settlement wording, source ambiguity, timing boundaries, order-book depth, sprea Inputs: market, intended_action, estimated_notional_usd, execution_mode, geographic_eligibility |
evaluate_tool_risk | Make a contextual allow, review, or block decision before an AI Agent installs or invokes a third-party tool registered in 404.directory. Use this immediately before installation or first use, and again when permissions, data sensitivity, e Inputs: target, action, data_sensitivity, execution_mode, permissions |
get_capability_graph | Return a Capability Graph snapshot (nodes, shared-capability edges, capability index) for agent planning. Inputs: limit, min_similarity |
get_tool | Fetch one registered ecosystem tool by id or slug, including trust profile and usage stats. Inputs: id_or_slug |
get_trust_score | Return the machine-readable Trust Profile for a catalog tool (ownership, availability, compatibility, security, usage). Inputs: id_or_slug |
inspect_tool_server | Live-inspect one active, provider-verified, operator-curated public MCP server from the 404.directory catalog. Returns only the remote read-only tools approved for gateway execution, including their current descriptions, JSON input schemas, Inputs: id_or_slug |
invoke_registered_tool | Invoke exactly one approved read-only tool on an active, provider-verified, operator-curated public MCP server registered in 404.directory. First use search_tools to select a server, then inspect_tool_server to obtain the current tool name Inputs: server_id_or_slug, tool_name, arguments |
list_capabilities | List capabilities in the 404 catalog with tool counts. Use to explore the Capability Graph before searching. |
recommend_tools | Given one known tool, recommend similar catalog tools via the Capability Graph (shared capabilities + protocol/category affinity). Inputs: id_or_slug, limit |
report_prediction_market_outcome | Close the behavioral feedback loop for one prior evaluate_prediction_market receipt. Call after the Agent proceeds, reduces position size, changes side, waits, requests review, aborts, or encounters an execution failure. Submit only the bou Inputs: outcome_token, action_taken, execution_result, failure_type, receipt_id |
report_tool_outcome | Close the feedback loop for one prior evaluate_tool_risk receipt. Call after the Agent proceeds, changes tools, requests review, or aborts. Submit only the bounded action/result fields and one-time outcome token returned by the evaluation; Inputs: outcome_token, action_taken, result, error_type, receipt_id |
search_official_docs | Search current first-party OpenAI, Microsoft Learn, AWS, and Cloudflare documentation in one call. Use this as the default documentation research tool for questions involving any of those providers, especially comparisons or cross-cloud arc Inputs: query, sources, limit_per_source |
search_tools | Find third-party catalog tools using short provider/capability keywords, for example 'official documentation' or 'OpenAI docs'. All meaningful query terms must match across name, description, capability, category or provider; exact names ra Inputs: q, capability, protocol, category, trust_threshold, limit |
understand_webpage | Reads one public human-facing webpage and returns a compact, evidence-linked AgentPageModel: page type, entities, login/current state, forms, enabled actions, and confidence. Prefer this over generic web search when the question is what is Inputs: url |
verify_web | Independently verifies that a public website is reachable and meets deployment expectations (HTTP status, HTTPS validity, optional expected text). Returns structured evidence for accept / retry / escalate decisions. When to use: Use when th Inputs: url, expected_status, expected_text |
Every block below points at https://404.directory/mcp. Pick your client and copy.
claude mcp add --transport http 404-directory https://404.directory/mcp
{
"mcpServers": {
"404-directory": {
"command": "npx",
"args": ["-y", "mcp-remote", "https://404.directory/mcp"]
}
}
}{
"mcpServers": {
"404-directory": {
"url": "https://404.directory/mcp"
}
}
}{
"servers": {
"404-directory": {
"type": "http",
"url": "https://404.directory/mcp"
}
}
}{
"context_servers": {
"404-directory": {
"url": "https://404.directory/mcp"
}
}
}{
"mcpServers": {
"404-directory": {
"serverUrl": "https://404.directory/mcp"
}
}
}{
"mcpServers": {
"404-directory": {
"url": "https://404.directory/mcp"
}
}
}name: 404.directory
version: 0.0.1
schema: v1
mcpServers:
- name: 404.directory
type: streamable-http
url: https://404.directory/mcp{
"mcpServers": {
"404-directory": {
"httpUrl": "https://404.directory/mcp"
}
}
}{
"mcpServers": {
"404-directory": {
"type": "http",
"url": "https://404.directory/mcp"
}
}
}{
"mcpServers": {
"404-directory": {
"url": "https://404.directory/mcp"
}
}
}goose://extension?url=https%3A%2F%2F404.directory%2Fmcp&type=streamable_http&id=404-directory&name=404.directory
It answered our last check on 20 October 2026 in 661 ms. Over 6 checks since 11 September 2026 it answered 5. Status here comes from Neuronto's own probes, not from the publisher.
16, as returned by the server's own tools/list on 12 September 2026: compare_tools, evaluate_prediction_market, evaluate_tool_risk, get_capability_graph, get_tool, get_trust_score, inspect_tool_server, invoke_registered_tool, and 8 more.
It answered our last check on 20 October 2026 in 661 ms. Over 6 checks since 11 September 2026 it answered 5.
Put the server under mcpServers in ~/.cursor/mcp.json with the URL https://404.directory/mcp. The exact JSON is above, with the same setup for Claude Code, Claude Desktop, VS Code, Windsurf, Zed, Gemini CLI and the rest.
It listed its tools to an anonymous client, so reading the tool list needs no key. Individual tools can still ask for credentials in their own inputs.
Publisher: io.github.mm-sheng. Endpoint host: 404.directory. ARD identifier: urn:air:io.github.mm-sheng:mcp:404-directory.
First indexed 10 September 2026. The tools are exactly what the server returned; nothing on this page
is inferred from its name. Ranking in Neuronto search is never for sale.