Deadends.Dev MCP Server

Structured failure knowledge for AI agents — dead ends, workarounds, error chains

Local serverstdioPython

What is the Deadends.Dev MCP server?

Connect Deadends.Dev to Claude, Cursor or any other MCP client and it stops being a tab you switch to. Structured failure knowledge for AI agents — dead ends, workarounds, error chains. The deadends.dev mcp server is what makes that connection.

What the server does

AI assistants reliably fumble two kinds of problems: known-failed code fixes, and country-specific real-world rules they've never been exposed to in training. deadends.dev now covers both:

  • Deterministic — Same query → same answer, every time. No hallucination
  • Country-scoped — ID format {domain}/{slug}/{env} - env holds the country
  • Primary-sourced — Every country canon cites government sites, embassies,
  • Community-validated — Fix success rates updated from real outcome reports
  • Sub-millisecond — Local regex matching, no API roundtrip

Available tools

The toolset is worth reading before you wire it up, because it tells you what the integration is really for:

  • lookup_error — Match an error message against 2000+ known patterns
  • get_error_detail — Full canon by ID
  • list_error_domains — All 54 domains with counts
  • search_errors — TF-IDF keyword search across all domains
  • list_errors_by_domain — All errors in a domain
  • list_errors_by_country — All country-scoped dead ends for an ISO alpha-2 code
  • get_country_summary — Country-level summary (entries, fix rate, domain mix)
  • batch_lookup — Look up multiple errors at once (max 10)
  • get_domain_stats — Domain quality metrics and confidence levels
  • get_error_chain — Traverse the error transition graph
  • report_outcome — Report whether a workaround worked (feeds back into success rates)
  • Endpoint — Description

Installation

Installation goes through your MCP client rather than a global install: point it at @smithery/cli on npm and it is fetched when the client starts. The copy-paste blocks for Claude Desktop, Claude Code and Cursor are further down this page.

Where it fits

This sits in the developer tooling group, where several servers overlap in what they claim to do but differ sharply once you actually set them up. Deadends.Dev's toolset — lookup_error, get_error_detail, list_error_domains and 9 more — is a fair guide to whether it matches your workflow. It is maintained by dev.deadends; worth a glance at recent repository activity before you build anything load-bearing on it.

This entry was verified against Deadends.Dev's own documentation before publication; SyncDev keeps the directory reviewed rather than auto-generated.

Worth knowing first

  • It runs with your machine's permissions. That is convenient and also the reason to think about what you point it at before you approve a tool call.
  • With 12 tools registered it takes up a noticeable share of the context window; turn it off in projects that never touch Deadends.Dev.
  • Keep per-call confirmation enabled while you learn its behaviour; it is the cheapest safeguard you have.

Available tools

ToolWhat it does
lookup_errorMatch an error message against 2000+ known patterns
get_error_detailFull canon by ID
list_error_domainsAll 54 domains with counts
search_errorsTF-IDF keyword search across all domains
list_errors_by_domainAll errors in a domain
list_errors_by_countryAll country-scoped dead ends for an ISO alpha-2 code
get_country_summaryCountry-level summary (entries, fix rate, domain mix)
batch_lookupLook up multiple errors at once (max 10)
get_domain_statsDomain quality metrics and confidence levels
get_error_chainTraverse the error transition graph
report_outcomeReport whether a workaround worked (feeds back into success rates)
EndpointDescription

How to install the Deadends.Dev MCP server

{
  "mcpServers": {
    "deadend": {
      "serverUrl": "https://deadends.dev/mcp",
      "type": "http"
    }
  }
}

Configuration as documented by the project. Restart the client after saving.

Example prompts to try

  • Use Deadends.Dev to lookup error.
  • Use Deadends.Dev to get error detail.
  • Use Deadends.Dev to list error domains.

Frequently asked questions

It connects Deadends.Dev to MCP-compatible AI assistants such as Claude and Cursor, exposing 12 tools (lookup_error, get_error_detail, list_error_domains, and more) that the assistant can call on your behalf. Instead of copying data back and forth by hand, the assistant works with Deadends.Dev directly.