Getting it into your agent
One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.
npx agentmods add agents/lazy-coder-03/leftbrain/authgit clone --depth 1 https://github.com/Lazy-Coder-03/leftbrainWhat it costs to keep this loaded
Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5 | $0.00000 | $0.01747 |
| Opus 5 | $0.00000 | $0.00873 |
| Sonnet 5 | $0.00000 | $0.00349 |
| Haiku 4.5 | $0.00000 | $0.00175 |
Grade A, and why
auth scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured yesterday.
A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.
Nothing flagged
None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.
How it starts
The opening of the file, as written. The whole thing — 190 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Authenticating: a guide for agents
This page is written for a model, not a person. It is the whole of what leftbrain expects, in the
order you will need it. Every path below is relative to https://leftbrain.idlesync.in.
Read the section that matches your situation and stop.
1. You were given a key
If you hold a string starting lblz_, send it and you are done. There is no OAuth to do.
:::request
POST /mcp
Authorization: Bearer lblz_YOUR_KEY
Accept: application/json, text/event-stream
Content-Type: application/json
:::
Everything else on this page exists for the case where nobody handed you one.
2. You got a 401
The body tells you what to do next, and the header tells you where the metadata is.
:::response
{
"ok": false,
"error": "missing key",
"message": "send Authorization: Bearer <key>",
"how_to_authorize": {
"if_you_have_a_browser": "https://leftbrain.idlesync.in/.well-known/oauth-protected-resource/mcp",
"if_you_have_no_browser": "POST https://leftbrain.idlesync.in/oauth/device_authorization",
"tell_your_user": "leftbrain needs authorising. I can give you a short code to approve at https://leftbrain.idlesync.in/device",
"static_key_alternative": "https://leftbrain.idlesync.in/dashboard",
"documentation": "https://leftbrain.idlesync.in/docs/agents/auth"
}
}
:::
Discovery, if you are following the MCP specification rather than this page:
GET /.well-known/oauth-protected-resource/mcp— names the authorization server.GET /.well-known/oauth-authorization-server— names/authorize,/token,/register,/revokeand/oauth/device_authorization.
Then choose section 3 or section 4 by whether you can open a browser and receive a redirect on a loopback port. If either is false, use section 4.
3. You can open a browser
Standard OAuth 2.1 authorization code with PKCE. S256 is required; plain is refused.
Identify yourself. Either host a Client ID Metadata Document and use its HTTPS URL as your
client_id (preferred — nothing to register, and it works against any server), or register:
What this file has done since we first saw it
Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.
- yesterday First seen · 190 lines · 0 tokens per session scan A e44d9ed7e56d
auth is an agent published in the GitHub repository Lazy-Coder-03/leftbrain (0 stars, last pushed yesterday), licensed MIT. It costs nothing until one of its globs matches a file; then it loads 1,747 tokens. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-31.
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