@sirrlock/mcp — Sirr MCP Server

Gives AI assistants like Claude direct access to your Sirr secret vault. Push, read, and manage ephemeral secrets without leaving a conversation.

Demo

Session 1 — store the secret

❯ set the BITBUCKET_TOKEN to 123asdzxc

⏺ sirr-mcp - push_secret (MCP)(key: "BITBUCKET_TOKEN", value: "123asdzxc", max_reads: 1)
  ⎿  Stored secret 'BITBUCKET_TOKEN'. Burns after 1 read.

⏺ Stored. Burns after first read.

Session 2 — Claude retrieves and uses it (the vault burns it)

❯ deploy to staging using sirr:BITBUCKET_TOKEN

⏺ sirr-mcp - get_secret (MCP)(key: "BITBUCKET_TOKEN")
  ⎿  123asdzxc

⏺ Got it. Deploying to staging with the token. Done.

Session 3 — secret is already gone

❯ what is the BITBUCKET_TOKEN?

⏺ sirr-mcp - get_secret (MCP)(key: "BITBUCKET_TOKEN")
  ⎿  Secret 'BITBUCKET_TOKEN' not found, expired, or already burned.

⏺ The secret no longer exists on the server.

The secret existed just long enough to be used once. The vault enforces it server-side (max_reads=1). Claude is instructed by the tool description not to memorize or repeat the value. Even if a different agent, session, or attacker asks — there is nothing left to return.

Install

npm install -g @sirrlock/mcp

Or use npx without a global install — see the configuration block below.

Quick start

Start Sirr — run the Sirr server and note the SIRR_MASTER_KEY you set (or the one it printed on first launch).
Set your token — SIRR_TOKEN in your MCP config must equal that SIRR_MASTER_KEY value exactly.
Add to .mcp.json — paste the config block below, substituting your server URL and key.
Verify — run sirr-mcp --health to confirm the connection before starting your AI session.

Configuration

Add Sirr to your project's .mcp.json or ~/.claude/settings.json:

{
  "mcpServers": {
    "sirr": {
      "command": "sirr-mcp",
      "env": {
        "SIRR_SERVER": "http://localhost:39999",
        "SIRR_TOKEN": "your-sirr-master-key"
      }
    }
  }
}

Using npx without a global install:

{
  "mcpServers": {
    "sirr": {
      "command": "npx",
      "args": ["-y", "@sirrlock/mcp"],
      "env": {
        "SIRR_SERVER": "http://localhost:39999",
        "SIRR_TOKEN": "your-sirr-master-key"
      }
    }
  }
}

What is SIRR_TOKEN? It is the value of SIRR_MASTER_KEY that you set (or that was generated) when you started the Sirr server. These two values must match exactly — a mismatch is the most common cause of 401 errors. See sirr.dev/errors#401.

Environment variables

Variable	Default	Description
`SIRR_SERVER`	`http://localhost:39999`	Sirr server URL
`SIRR_TOKEN`	—	Bearer token — must equal `SIRR_MASTER_KEY` on the server

CLI flags

# Print the installed version and exit
sirr-mcp --version

# Check that the MCP server can reach Sirr and exit
SIRR_SERVER=http://localhost:39999 SIRR_TOKEN=mykey sirr-mcp --health

--health exits with code 0 on success and 1 on failure, making it safe to use in scripts and CI.

Available tools

Secrets

Tool	Description
`get_secret(key)`	Retrieve a secret value (increments read counter; burns if max_reads reached)
`push_secret(key, value, ttl_seconds?, max_reads?)`	Store a secret with optional expiry and read limit
`list_secrets()`	List all active secrets — metadata only, values never returned
`delete_secret(key)`	Burn a secret immediately, regardless of TTL or read count
`prune_secrets()`	Delete all expired secrets in one sweep
`health_check()`	Verify the Sirr server is reachable and healthy

Audit

Tool	Description
`sirr_audit(since?, action?, limit?)`	Query the audit log — secret creates, reads, deletes, and key events

Webhooks

Tool	Description
`sirr_webhook_create(url, events?)`	Register a webhook URL; returns ID and signing secret (shown once)
`sirr_webhook_list()`	List all registered webhooks (signing secrets redacted)
`sirr_webhook_delete(id)`	Remove a webhook by ID

API keys

Tool	Description
`sirr_key_create(label, permissions, prefix?)`	Create a scoped API key; raw key returned once — save it
`sirr_key_list()`	List all scoped API keys (key hashes never returned)
`sirr_key_delete(id)`	Delete an API key by ID

Inline secret references

You can reference secrets inline in any prompt:

"Use sirr:DATABASE_URL to run a migration"
"Deploy with sirr:DEPLOY_TOKEN"

The sirr:KEYNAME prefix tells Claude to fetch from the vault automatically.

Security notes

Claude only sees secret values when you explicitly ask it to fetch via get_secret
list_secrets returns metadata only — values are never included
Set max_reads=1 on any secret shared for a single AI session
The MCP server never logs secret values
SIRR_TOKEN lives in your MCP config's env block — it is never passed as a tool argument or in prompts
Use HTTPS (https://) when SIRR_SERVER points to a remote host — plain HTTP transmits secrets unencrypted

Troubleshooting

Symptom	Cause	Fix
`Error: Sirr 401`	`SIRR_TOKEN` doesn't match `SIRR_MASTER_KEY`	Verify both values match exactly — no extra spaces or newlines. sirr.dev/errors#401
`Error: Sirr 402`	Free-tier limit of 100 secrets reached	Delete unused secrets or add a `SIRR_LICENSE_KEY`. sirr.dev/errors#402
`Error: Sirr 403`	Scoped API key lacks the required permission	Re-create the key with the needed permissions. sirr.dev/errors#403
`Secret '…' not found`	Secret expired, was burned, or key was mistyped	Re-push the secret if you still need it. sirr.dev/errors#404
`did not respond within 10s`	Sirr server is unreachable	Check `SIRR_SERVER` URL and confirm Sirr is running (`sirr-mcp --health`).
`[sirr-mcp] Warning: SIRR_TOKEN is not set`	Token missing from MCP config	Add `SIRR_TOKEN` to the `env` block in `.mcp.json`.
MCP server not found by Claude	`sirr-mcp` not on PATH	Install globally (`npm install -g @sirrlock/mcp`) or use the `npx` config variant.

Package	Description
sirr	Rust monorepo: `sirrd` server + `sirr` CLI
@sirrlock/node	Node.js / TypeScript SDK
sirr (PyPI)	Python SDK
Sirr.Client (NuGet)	.NET SDK
sirr.dev	Documentation
secretdrop.app	Hosted service + license keys

@sirrlock/mcp — Sirr MCP Server