Report the client environment on API requests

[kylegani]

Why

Deploy attribution today cannot tell an agent-driven deploy from a human one. X-Source: cli and X-CLI-Version are already sent on every request, but neither says what invoked the CLI, so every automated deploy lands in the same bucket as an engineer at a terminal. The mission-control agents page reports a ~32% automation share of deploying principals against a ~70% automation share of build volume, and that gap is currently an undifferentiated blob: service accounts used by CI, by coding agents, and by internal tooling all look identical.

What

A new internal/clientenv package classifies the invoking environment and emits it as X-Client-Env alongside the existing source and version headers. Three shapes:

• agent:<name> for a detected coding agent (claude, cowork, cursor, cursor-cli, codex, gemini, antigravity, augment-cli, opencode, github-copilot, devin, plus anything self-declared via AI_AGENT)
• ci for a CI system (CI plus 13 vendor-specific variables)
• interactive otherwise

The header goes on the JSON API client, the multipart RunApp path, and both device-auth endpoints. Value is computed once per process via sync.Once.

Design constraints held

Detection never influences behaviour. No output-format default, no confirmation-prompt suppression, no branch anywhere reads this classification. It is observational only, which is why the non-TTY deploy guard shipped in #87 keys off stdin TTY-ness rather than agent detection. Detect takes its environment lookup and filesystem probe as parameters so the whole matrix is testable without touching the real environment.

AI_AGENT values are untrusted. Lowercased, restricted to [a-z0-9._-], capped at 64 characters. A value that sanitizes to nothing becomes agent:unknown rather than silently degrading to interactive, so a declared-but-unparseable agent still lands in the agent bucket.

REPL_ID is deliberately not a detector. It reports that the process runs on Replit, not that an agent drives it, so keying on it would classify humans working in the Replit editor as agents. A Replit agent that sets AI_AGENT is still detected. This reverses an earlier draft of this branch that mapped REPL_ID to agent:replit; the test now pins the corrected behaviour both ways.

Agent detection precedes CI detection, because an agent running inside a CI job is more specifically an agent, and the hosted-agent surfaces we care about all set CI too.

Rider: DO_NOT_TRACK

pkg/bugsnag previously ignored DO_NOT_TRACK and only honoured the CLI's own telemetry config. It now disables error reporting when DO_NOT_TRACK is set to anything other than empty, 0, or false, matching the config-based path.

X-Client-Env itself is still sent under DO_NOT_TRACK. It carries no identity, no machine identifier and no path: it is one enum value on an already-authenticated request, in the same class as the X-Source and X-CLI-Version headers that have always been sent unconditionally. Flagging it here as a deliberate call rather than an oversight.

Validation

• go test ./internal/clientenv/... ./internal/api/... ./internal/auth/... ./pkg/bugsnag/... green. 30+ detection cases, header-presence tests on both the API client and the OAuth endpoints, and a DO_NOT_TRACK matrix.
• gofmt clean. golangci-lint on the touched packages reports one finding, nilerr in internal/auth/docker.go, verified pre-existing by re-running against a stash of this branch.
• Repo-wide make lint and go build ./... fail on vendored cortex/server/node_modules AWS CDK templates, unrelated to this change and present on main.

Depends on

Nothing to work, but the header is only stored once dashboard-backend PR #4126 lands. Until then it is accepted and discarded.

[kylegani]

Superseded by #101: rebranched to feat/cli-client-env-header to match the repo's branch and conventional-commit conventions, and the detector matrix was reworked against the vercel/detect-agent registry (8 agents were missing, 4 identifiers diverged, 3 env vars unread).