Reference
The Argus API
Argus keeps a local HTTP server open while the launcher is running. Point your own code at it, or hand it to a coding agent over MCP — the same capabilities either way.
On this page
What this is
This is a local API. It listens on loopback on the machine running Argus, and nothing off that machine can reach it. There is no hosted web API.
The server starts with the launcher and stops with it. Everything it can do happens on this machine: it opens profiles in the Argus browser, reads and changes the ones you already have, and runs the automations you have authored.
- Base URL
- http://127.0.0.1:39219
- Auth
- Authorization: Bearer <YOUR_API_KEY>
- Bodies
- Content-Type: application/json
- Surface
- 130 endpoints · 143 agent tools
- Plan
- Every plan, including Free
The API and the MCP tools are on every plan, including Free. A plan sets how many profiles, seats and automations a workspace gets — it does not decide whether the API answers.
This page is also published for machines: /api-reference.md is everything below as one Markdown document, and /openapi.json is the same table as an OpenAPI 3.1 spec. Both are generated from the file this page renders, so neither can drift from it.
All three, the assistant's skill library, and drop-in rules for your own CLAUDE.md or AGENTS.md are published at github.com/pochtmanr/argus-mcp, generated from this site rather than maintained beside it.
Deleting a profile is the one half-move. It goes to Trash over the API and can be brought back; the irreversible purge stays an in-app action, so a script cannot destroy an identity outright.
Two ways in
The same capabilities, reached two ways. Which you want depends on whether you are writing the code or an agent is.
MCP, for AI agents
143 tools an agent discovers on its own — no wrapper to write and nothing to keep in step with a changelog.
HTTP, for your own code
Plain JSON over loopback. Anything that can send a request can drive a profile — no SDK, and no library to install.
Create a key, and the first call is one line:
curl -s "http://127.0.0.1:39219/v1/profiles" \
-H "Authorization: Bearer <YOUR_API_KEY>"Keys and approval
- Keys are created in the launcher, under the API tab. The raw value is shown once, at creation — only a hash is stored, so a lost key is replaced rather than recovered.
- A key can be scoped to specific folders, or left unscoped. A scoped key sees only the profiles in its folders, and may only close a session it opened itself.
- The first time a new client calls the API, the launcher raises an approve-or-deny prompt and holds the request until you answer it.
A launched session carries whatever identity the profile already holds, including its cookies — so it may well open already signed in. Do not send it anything the profile is not meant to have. The launch reply carries a `warnings` array: a non-empty one means that profile shares its cookie set or its proxy past the limit, which for a cookie set means the account is signed in from another profile too. Launching is not blocked for it, but say so rather than opening a batch silently, and call `argus_sharing_report` before a batch to see the whole picture in one call.
Reference
Every endpoint, and the agent tool fronting it where one exists. A row marked HTTP only has no tool on purpose: an agent cannot call it, however plainly it is documented here.
130 endpoints · 143 agent tools
Handing this to a coding agent? Take the whole reference — every endpoint, its fields and its curl — as one Markdown document.
What the errors mean
Every response carries a status boolean; a failure adds a msg saying what went wrong. Two of these are routinely misread as “retry me”.
- 401
- No bearer token, or one that does not match a stored key.
- 403
- The key is scoped to folders that do not contain that profile, or it is trying to author an automation while folder-scoped. Not a missing profile, and not worth retrying.
- 400
- The body failed validation. The message names the exact path that failed.
- 404
- No such route.
- 501
- A documented route that is not implemented yet.
- 503
- Argus Launcher is not open. Nothing can answer until it is.
- 504
- The launcher window did not answer in time.
4xx fix the request5xx fix the launcher
Get the launcher
The API is part of it. Create a key under the API tab and you are calling this in a minute.