# GitHub accounts: how the agent authenticates

How the agent's `gh` and `git push` authenticate, and how the GitHub notification poller works. What an operator does to give an agent an account is in [GitHub accounts](../../2-handbook/external-accounts/github.md).

## How the agent uses it

When enabled, the container gets:

- **A `gh` wrapper** on `PATH` (shadowing the raw `gh`) that exports
  `GH_TOKEN` from the token file at invocation, then execs real `gh`. So
  `gh pr create`, `gh api …`, etc. just work — `gh` derives the identity
  from the token.
- **A git credential helper** (`git-credential-hive-github`), wired via a
  host-scoped `/etc/gitconfig` entry for `https://github.com`, so
  `git push https://github.com/<owner>/<repo>` authenticates as
  `x-access-token` + the PAT (GitHub ignores the username for PAT auth).
  Host-scoped, so it never touches the forge (`localhost:3000`) or any
  other remote.

Both scripts read the token from `<state>/github-token` **at invocation
time**, so a PAT written (or rotated) mid-session takes effect immediately
— no container rebuild or restart. Until the file exists, `gh` / `git push`
fail unauthenticated. The build bakes the token path into the scripts
(rather than reading it from an env var), because claude's Bash tool runs in a
minimal environment that wouldn't carry one.

## Notifications

`hive-github-notify` polls github.com for the agent, turning each unread
notification thread into a todo. it's a **separate binary and a
separate systemd unit** from the internal forge's poller
(`hive-forge-notify`, see [the forge notification poller](forge-notify.md)),
installed by `nix/agent-modules/github.nix` under
`services.hyperhive.agent.github.enable`. Both binaries ship from the one
`hive-forge-notify` derivation, so the unit is a second `ExecStart`
path, not a new package.

Two units rather than one daemon with two loops, because it puts the
decision in nix: a hive built without this module has **no github poller
in its closure at all**, which is what makes GitHub access separable
rather than merely switched off. it's also why this isn't a cargo
feature — a feature would unify across the workspace and cost every
crate its build cache.

At runtime the poller needs the PAT above. No PAT, no polling: the unit
logs why and exits 0, which is why it's `Restart = on-failure` and
never `always` — a clean exit on a PAT-less agent must not become a
restart loop. The poller waits about ten minutes for the PAT to appear
before it gives up. A path unit (`hive-github-notify.path`) starts the poller
again when `<state>/github-token` changes, so a PAT that lands later still
enables polling. Once polling, it re-reads the file on every
tick, so it picks up a rotated PAT on the next tick without a restart.

Forgejo models its notifications API on GitHub's, so one tolerant
parse serves both: `id`, `repository.full_name`,
`subject {title,url,latest_comment_url}` and `updated_at` line up field
for field. Lenient deserializers absorb the two real differences —
GitHub sends the thread id as a _string_ where Forgejo
sends a number, and says `PullRequest` where Forgejo says `Pull`.
`hive-github-notify` prefixes todo keys `gh:<id>` so a github thread id can't collide with a
forge one.

Two host differences worth knowing before touching this code:

- **Auth scheme, not just value.** Forgejo takes
  `Authorization: token <t>`; GitHub wants `Bearer <t>` plus `Accept:
application/vnd.github+json`, `X-GitHub-Api-Version` and a
  `User-Agent`. Sending Forgejo's form to GitHub doesn't error — it
  authenticates as _nobody_ and silently drops to the unauthenticated
  rate limit. The cheap way to tell the two apart is the rate-limit
  header: `x-ratelimit-remaining` near 5000 is an authenticated user,
  near 60 is anonymous.
- **GitHub sets the cadence.** It returns `X-Poll-Interval` (60s in
  practice, slower than the poller's own tick) and rate-limits callers who
  ignore it, so the loop re-arms to the server's interval whenever that's
  _slower_ than the poller's. A hint faster than the poller's own tick
  isn't a reason to poll harder.

⚠️ **This needs the `notifications` scope on the PAT.** A token minted
for `gh` + `git push` typically carries `repo` only, which is enough to
push and open PRs but **not** to read the notification stream (nor to
mark a thread read, which is the same scope). A PAT without it doesn't
break anything: the poller logs the refusal and stays quiet, and the
agent never gets GitHub wakes. If an agent's GitHub
notifications never arrive, check the token's scopes first — the
symptom is silence, not an error.