Fireweed — Claude Code MCP server: evidence-backed memory
Fireweed stores claims with source evidence, rejects unsupported details, and can certify erasure. It suits agent workflows where you need to audit what entered memory.
claude mcp add fireweed-mcp -- uvx fireweed-mcpWhat Fireweed does
An agent sends remember a claim and the text meant to support it. Deterministic checks reject claims that add details beyond the cited passage; accepted records retain the source byte range. verify_receipts rechecks source content, while trace_evidence follows a record back to the document and ledger event.
recall returns grounded records or abstains when it cannot support an answer. Retrieval is a real limitation: in the reported test with unseen question phrasings, the default install refused 99.2% of queries. forget removes records and issues a signed certificate; export_memory produces a portable open-format store. The server does not extract facts from free text on its own. An agent must supply claims and evidence.
Install it with uvx; no API key or model is needed, and the server does not call an LLM. Data lives in ~/.fireweed/mcp/, configurable through FIREWEED_MCP_STORE. Avoid fireweed-mcp[semantic]: on absent-answer tests, correct refusals fell from 96.1% to 32.8%.
What it helps with
- store a claim only when its cited passage supports it
- check whether source bytes have changed since a fact was recorded
- trace a memory back to its source document and ledger event
- erase a person's records and obtain a signed certificate
- export the memory store in a portable open format
Example prompts for the agent
- Save the claim that Priya Raman joined Acme as a logistics analyst in 2019, with a passage that supports it.
- Check whether the memory contains evidence about Priya's salary, and abstain if the source does not support an answer.
- Remove Priya's records from memory and return the erasure certificate.
How to install Fireweed
Platform CLI
claude mcp add fireweed-mcp -- uvx fireweed-mcpuvx runs the command named after the package; if the README names another one, use uvx --from fireweed-mcp <command>
Platform CLI
codex mcp add fireweed -- uvx fireweed-mcpuvx runs the command named after the package; if the README names another one, use uvx --from fireweed-mcp <command>
Config file
{
"mcpServers": {
"fireweed": {
"command": "uvx",
"args": [
"fireweed-mcp"
]
}
}
}uvx runs the command named after the package; if the README names another one, use uvx --from fireweed-mcp <command>
Config file
{
"servers": {
"fireweed": {
"type": "stdio",
"command": "uvx",
"args": [
"fireweed-mcp"
]
}
}
}uvx runs the command named after the package; if the README names another one, use uvx --from fireweed-mcp <command>
Platform CLI
gemini mcp add fireweed uvx fireweed-mcpuvx runs the command named after the package; if the README names another one, use uvx --from fireweed-mcp <command>
Step by step, with commands for each platform: How to add an MCP server to Claude Code, Codex, Cursor, VS Code, Gemini CLI and more
Questions about Fireweed
How do I install Fireweed in Claude Code?
Run claude mcp add fireweed-mcp -- uvx fireweed-mcp to add the Fireweed MCP server.
What does Fireweed do?
It checks claims against supplied evidence before storing them, keeps source ranges for auditing, and supports certified erasure. It does not extract facts from free text by itself.
Can Fireweed reliably retrieve records from unfamiliar question phrasing?
In the reported test with unseen phrasings, the default install refused 99.2% of queries. The optional semantic mode also reduced correct refusals on absent-answer tests from 96.1% to 32.8%.
