Click on "Install Server".
Wait a few minutes for the server to deploy. Once ready, it will show a "Started" state.
In the chat, type
@followed by the MCP server name and your instructions, e.g., "@Sirr MCP Serverfetch the DATABASE_URL secret from my vault"
That's it! The server will respond to your query, and you can continue using it as needed.
Here is a step-by-step guide with screenshots.
@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/mcpOr use npx without a global install — see the configuration block below.
Quick start
Start Sirr — run the Sirr server and note the
SIRR_MASTER_KEYyou set (or the one it printed on first launch).Set your token —
SIRR_TOKENin your MCP config must equal thatSIRR_MASTER_KEYvalue (or a principal key for org-scoped access).Add to
.mcp.json— paste the config block below, substituting your server URL and key.Verify — run
sirr-mcp --healthto 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? For single-tenant usage, set it toSIRR_MASTER_KEY(full access). For multi-tenant org-scoped usage, set it to a principal key. A mismatch is the most common cause of 401 errors. See sirr.dev/errors#401.
Environment variables
Variable | Default | Description |
|
| Sirr server URL |
| — | Bearer token — |
| — | Organization ID for multi-tenant mode. When set, all secret/audit/webhook/prune paths are prefixed with |
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 |
| Check if a secret exists and inspect its metadata — without consuming a read |
| Retrieve a secret value (increments read counter; burns if max_reads reached) |
| Store a secret with optional expiry, read limit, and seal behavior |
| Update an existing secret's value, TTL, or read limit |
| List all active secrets — metadata only, values never returned |
| Burn a secret immediately, regardless of TTL or read count |
| Delete all expired secrets in one sweep |
| Verify the Sirr server is reachable and healthy |
Audit
Tool | Description |
| Query the audit log — secret creates, reads, deletes, and key events |
Webhooks
Tool | Description |
| Register a webhook URL; returns ID and signing secret (shown once) |
| List all registered webhooks (signing secrets redacted) |
| Remove a webhook by ID |
Principal keys
Tool | Description |
| List all API keys for the current principal |
| Create a new API key; raw key returned once — save it |
| Revoke an API key by ID |
Account (principal-scoped)
Tool | Description |
| Get the current principal's profile, role, and key list |
| Replace the current principal's metadata |
Organizations
Tool | Description |
| Create a new organization |
| List all organizations (master key only) |
| Delete an organization — must have no principals |
Principals
Tool | Description |
| Create a principal (user or service account) in an org |
| List all principals in an org |
| Delete a principal — must have no active keys |
Roles
Tool | Description |
| Create a custom role. Permissions: C=create R=read P=patch D=delete L=list M=manage A=admin |
| List all roles in an org (built-in and custom) |
| Delete a custom role — must not be in use |
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.
Secret lifecycle
Sirr secrets expire by design. The push_secret tool lets you control exactly how:
Option | Behavior |
| Secret expires after 1 hour, regardless of reads |
| Secret is deleted after the first read |
| After 5 reads the secret is sealed (returns 410, stays in DB) instead of deleted |
No options | Secret persists until explicitly deleted |
Use check_secret to inspect a secret's status without consuming a read — useful when you want to verify a secret is still available before fetching it.
Security notes
Claude only sees secret values when you explicitly ask it to fetch via
get_secretlist_secretsreturns metadata only — values are never includedSet
max_reads=1on any secret shared for a single AI sessionThe MCP server never logs secret values
SIRR_TOKENlives in your MCP config'senvblock — it is never passed as a tool argument or in promptsUse HTTPS (
https://) whenSIRR_SERVERpoints to a remote host — plain HTTP transmits secrets unencrypted
Troubleshooting
Symptom | Cause | Fix |
|
| Verify both values match exactly — no extra spaces or newlines. sirr.dev/errors#401 |
| Free-tier limit reached | Delete unused secrets or upgrade. sirr.dev/errors#402 |
| Token lacks the required permission | Use a token with the needed scope. sirr.dev/errors#403 |
| Resource has dependencies | Remove dependents first (e.g. delete principals before org). sirr.dev/errors#409 |
| Secret expired, was burned, or key was mistyped | Re-push the secret if you still need it. sirr.dev/errors#404 |
| Sirr server is unreachable | Check |
| Token missing from MCP config | Add |
MCP server not found by Claude |
| Install globally ( |
Related
Package | Description |
Rust monorepo: | |
Node.js / TypeScript SDK | |
Python SDK | |
.NET SDK | |
Documentation | |
Hosted service + license keys |
Resources
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