About failmodes
failmodes is an MCP server that provides a machine-readable taxonomy of AI system failure modes. Its tools let agents and other MCP clients search and retrieve structured records across categories such as factuality, alignment, planning, and code generation.
Key features
- 01Search by symptom or keyword
- 02Retrieve a full record by ID
- 03List taxonomy categories
- 04List modes with category filtering
Use cases
- 01Find failure modes matching an observed symptom
- 02Retrieve details for a known failure mode
- 03Browse modes within a taxonomy category
MCP support
Exposes four tools to MCP clients for searching, retrieving, and listing failure-mode taxonomy data. It is available over stdio or as a hosted Streamable HTTP endpoint.
Configuration
Remote servers need no local install. Pick your client, then copy the config or install in one click.
https://www.failmodes.com/api/mcpclaude mcp add --transport http elyngved-failmodes https://www.failmodes.com/api/mcp{"mcpServers":{"elyngved-failmodes":{"type":"http","url":"https://www.failmodes.com/api/mcp"}}}Open in Cursor{"servers":{"elyngved-failmodes":{"type":"http","url":"https://www.failmodes.com/api/mcp"}}}Open in VS Code{"mcpServers":{"elyngved-failmodes":{"type":"http","url":"https://www.failmodes.com/api/mcp"}}}{"mcpServers":{"elyngved-failmodes":{"serverUrl":"https://www.failmodes.com/api/mcp"}}}Run commands in a terminal; paste JSON into the client’s MCP config and restart. Servers that need sign-in will prompt on first connect.
Tools
4| Parameter | Type | Required | Description |
|---|---|---|---|
| symptom | string | Yes | Symptom phrase or keyword to search for, e.g. 'made up a citation' or 'refused to help after pushback' |
Details
From the project READMEfailmodes-mcp
MCP server for the Fail Modes taxonomy — a machine-readable knowledge base of AI system failure modes.
Provides four tools over 100+ canonical failure mode records spanning factuality, alignment, planning, code generation, instruction following, and more.
Tools
| Tool | Description |
|---|---|
search_failure_modes | Search by symptom text or keyword phrase. Returns ranked matches. |
get_failure_mode | Retrieve the full structured record for a failure mode by ID slug. |
list_categories | List all taxonomy categories with descriptions and mode counts. |
list_modes | List all modes, optionally filtered by category ID. |
Quick Start
No installation required — run directly with npx:
npx failmodes-mcp
Configuration
Claude Desktop
Add to ~/Library/Application Support/Claude/claude_desktop_config.json (macOS) or %APPDATA%\Claude\claude_desktop_config.json (Windows):
{
"mcpServers": {
"failmodes": {
"command": "npx",
"args": ["-y", "failmodes-mcp"]
}
}
}
Cursor / VS Code
Add to your MCP settings file:
{
"mcpServers": {
"failmodes": {
"command": "npx",
"args": ["-y", "failmodes-mcp"]
}
}
}
Remote (no install required)
A hosted Streamable HTTP version is also available — no npm package needed:
{
"mcpServers": {
"failmodes": {
"url": "https://www.failmodes.com/api/mcp"
}
}
}
How It Works
On first tool call, the server fetches current taxonomy data from failmodes.com and caches it in memory for the duration of the session. Requires internet access.
The stdio transport makes this compatible with any MCP client that supports running local processes (Claude Desktop, Cursor, VS Code, etc.).
Links
- Taxonomy source: github.com/elyngved/failmodes-taxonomy
- Website: failmodes.com
- Remote MCP manifest: failmodes.com/server.json
License
MIT
Comments
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