Follow-up to #1328. That PR loosened the Cursor TERM_PROGRAM check from exact
`=== "cursor"` to `?.toLowerCase() === "cursor"` "for parity with Windsurf" —
but the parity is false. Windsurf is matched case-insensitively because its
sources genuinely disagree on casing ("windsurf" vs "Windsurf"); Cursor
consistently emits lowercase "cursor", so nothing justified loosening an
existing, working, exact-match rule. Per review feedback on #1328
(Magi/Hermes), revert Cursor to exact match and drop the TERM_PROGRAM=Cursor
test. Windsurf stays case-insensitive (sourced); its comment now documents the
asymmetry as intentional.
No functional change — Cursor always emitted lowercase, so detection is
unchanged; this just removes an unsourced false-positive surface.
Co-authored-by: Claude Fable 5 <noreply@anthropic.com>
Rebased onto main after #1294 merged. Adds four coding-agent vendors to
detectAgentRuntime() (existence-only checks, source/runtime-verified):
- windsurf — TERM_PROGRAM=windsurf (case-insensitive)
- cline — CLINE_ACTIVE (default vscode-terminal path)
- gemini_cli — GEMINI_CLI (runtime-confirmed; distinct from the managed-agent
/.agents/ detector, which runs ahead of VENDOR_RULES and wins when both match)
- crush — CRUSH (runtime-confirmed)
Also makes the cursor rule case-insensitive for parity with windsurf, and adds
a code-resident "deliberately NOT added" section (OpenHands/Aider/Goose/
opencode/Roo/Amp/Devin/Jules/Factory) carrying the empirical rejection
rationale.
Test isolation: the Gemini managed-agent suite now clears its node:os/node:fs
doMock registrations in afterEach so they don't leak into the env-var-only
suites that follow it in the same file.
Co-authored-by: Claude Fable 5 <noreply@anthropic.com>
* feat(cli): detect Gemini managed-agent sandbox in detectAgentRuntime
Add `gemini_managed_agent` to the AgentRuntime union and a dedicated
isGeminiManagedAgent() detector. Empirical signal pair (from live-sandbox
introspection by gemini-agent, env_id b9db4e56, 2026-06-09):
existsSync('/.agents/AGENTS.md') AND isGVisor()
The conjunction is what makes the rule safe:
- `/.agents/AGENTS.md` excludes generic gVisor surfaces (GKE Sandbox,
Cloud Run gen2) that don't mount the managed-agent layout.
- The gVisor kernel check excludes a dev box that happens to have a
stray `/.agents/` directory.
Implementation notes:
- Filesystem-based check runs ahead of the env-var-only VENDOR_RULES
loop. VENDOR_RULES is documented as "Only checks for the EXISTENCE
of well-known env vars — never reads their values"; the Gemini
signal is filesystem + kernel, not env, so it gets a dedicated
branch rather than shoehorning into the rule list.
- GEMINI_API_KEY is deliberately NOT keyed on — it's user-settable on
any host. The filesystem + kernel pair is the actually-distinctive
signal.
- Reuses the existing isGVisor() helper for the kernel half of the
conjunction; no duplication.
Tests (4 new, vitest):
- Positive: /.agents/AGENTS.md + 4.19.0-gvisor → gemini_managed_agent
- Negative: gVisor alone (no /.agents/) → null (generic gVisor surface)
- Negative: /.agents/AGENTS.md alone (no gVisor) → null (dev box false-positive guard)
- Precedence: Gemini signal wins over a coincident CLAUDECODE env var
Empirical caveat: signal was gathered from a single sandbox. Re-confirming
across additional sandbox spins is a follow-up; the rule is conservative
enough (conjunction of two independent signals) that a single-spin
false-positive is unlikely, but a single-spin variance bug (e.g. some
sandbox flavors omitting one of the two markers) would surface as
under-detection rather than over-detection.
Source for signals: introspection write-up at
/tmp/gemini-sandbox-detection-signals.md (gemini-agent, 2026-06-09).
* docs(cli): reframe Gemini-managed-agent detection rationale (load-bearing vs guard)
gemini-agent's uniqueness analysis (FS-root + cgroup + netns + DMI + PID-1
introspection of env d59d6361, 2026-06-09) revealed the two signals are
NOT co-equal:
- /.agents/AGENTS.md is the uniqueness anchor — definitionally a
managed-agent artifact, injected per-run by the platform, mtime
tracks the interaction. Nothing in the generic Google-Cloud-on-gVisor
universe (Cloud Run gen2, GKE Sandbox, Fly.io) mounts /.agents/.
- isGVisor() is a guard, not a second uniqueness signal. gVisor itself
is shared with GKE Sandbox + Cloud Run gen2 — its real job here is
ruling out a stray user-created /.agents/AGENTS.md on a non-sandbox
host.
The original 3-spin work proved *stability* (signals consistent across
sandbox spins). This pass adds *uniqueness* — confirming the signals
discriminate Antigravity from the broader gVisor universe, not just
that they're reliably present. Stability ≠ uniqueness; both are
required for a correct detection rule.
Code unchanged (the AND-gate is sound). Docstring reframed so a future
reader doesn't mistake the conjunction for two independent uniqueness
signals. Also enumerated the markers NOT keyed on (with reasons), so
future contributors don't reach for them by naming inference.
Source: gemini-agent uniqueness analysis write-up.
* fix(cli): key Gemini managed-agent detection on /.agents/ mount, not optional AGENTS.md
The detector keyed on existsSync('/.agents/AGENTS.md'), but Google's Managed
Agents docs are explicit that AGENTS.md is OPTIONAL: an agent may declare its
instructions inline via system_instruction in agent.yaml and ship no AGENTS.md
file ("system_instruction and AGENTS.md are additive; both apply when present").
The platform auto-discovers the agent under the /.agents/ directory; skills
mount at /.agents/skills/ and AGENTS.md at /.agents/AGENTS.md only when shipped.
Keying on the file generalized only to templates that happen to bundle an
AGENTS.md (like HeyGen's own gemini-agent and Thor's reference). A managed agent
defined with inline instructions or a skills-only definition was a silent
false-negative. All three prior verification spins used our own AGENTS.md-bearing
template, so the gap was never exercised.
Broaden to the /.agents/ directory mount (still gVisor-guarded — false-positive
surface is unchanged) so skills-only and inline-instruction agents are detected.
Adds a regression test for the skills-but-no-AGENTS.md case. Documents the one
residual gap (pure inline-only, no skills/no AGENTS.md) that needs an empirical
spin to confirm.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
* refactor(cli): tighten /.agents/ to a directory check + sync agent_runtime docs
Self-review follow-ups (no behavior change for real managed agents):
- isGeminiManagedAgent now requires statSync("/.agents").isDirectory() rather
than existsSync("/.agents"), matching the documented "directory mount"
contract. existsSync matched any entry (a stray file/symlink named /.agents),
widening the gVisor-gated false-positive surface beyond what the comment
claimed. Tests now mock statSync accordingly (and drop a dead /.agents/skills
mock clause the code never read).
- system.ts: the agent_runtime doc comment hard-coded the vendor list and said
"detected by env-var existence only" — both stale once a filesystem/kernel
detector (gemini_managed_agent) exists. Point at the AgentRuntime union and
note the filesystem-marker case instead.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
---------
Co-authored-by: Claude Fable 5 <noreply@anthropic.com>
Audit of every detection rule in the registry against actual vendor
source code. Rules that lacked a public-source citation were guesses
and have been removed; surviving rules now all cite the file + line
that emits the marker.
Codex — replace per @magi's investigation:
- Drop CODEX_HOME (config override read at startup, NOT propagated to
child processes — would miss most Codex invocations).
- Drop CODEX_SANDBOX (macOS Seatbelt only; covered by the others).
- Add CODEX_THREAD_ID (set unconditionally on every spawned shell
command — codex-rs/protocol/src/shell_environment.rs:6 +
codex-rs/core/src/unified_exec/process_manager.rs:1010).
- Add CODEX_CI (hardcoded in UNIFIED_EXEC_ENV — process_manager.rs:70).
- Keep CODEX_SANDBOX_NETWORK_DISABLED (default-on sandbox marker —
codex-rs/core/src/sandboxing/mod.rs:135-138).
Cursor — drop unverified CURSOR_TRACE_ID and CURSOR_AGENT guesses.
Keep TERM_PROGRAM=cursor (set by Cursor's integrated terminal).
Pi — new rule. https://github.com/earendil-works/pi
packages/coding-agent/src/cli.ts:13 unconditionally executes
process.env.PI_CODING_AGENT = "true";
at module entry, so every subprocess Pi spawns sees this marker.
Same propagation pattern as Hermes.
Removed (no source-cited marker found in this audit):
- aider — verified Aider sets no AIDER_* env vars; only OR_SITE_URL and
OR_APP_NAME (OpenRouter integration). No reliable marker.
- gemini_cli — GEMINI_SANDBOX/GEMINI_CLI_TRUST_WORKSPACE are conditional
on CLI flags; no unconditional marker found.
- jules, devin — closed source, no public marker documentation.
These vendors can be re-added later with a source citation; absence
in the registry will silently false-negative (events land in the null
bucket), but won't false-positive on other vendors.
Per @james-russo's review: do source-level research before shipping
detection rules. Memory updated to enforce this for future work.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Three follow-ups from @miguel-heygen's review:
1. HERMES_QUIET — switch to existence check.
`env["HERMES_QUIET"] === "1"` was brittle vs. future Hermes changes
(e.g. if cli.py ever sets it to "true"). The var name itself is
specific enough that existence is the right signal.
2. CI_PROVIDERS — convert to a discriminated union.
`mode: "truthy" | "presence"` is stricter than the previous pair of
optional boolean flags (which allowed entries with neither set).
3. Sandbox detection tests — add coverage.
- Docker positive: /.dockerenv present → docker.
- Negative case: plain Linux laptop with no markers → null.
Together with the gVisor 4.4.0 fix in the previous commit, that addresses
all three actionable callouts (the discriminated-union nit was non-blocking
but worth doing while in the file).
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Addresses PR feedback from @magi: kernel string `4.4.0` is also the
Ubuntu 16.04 LTS / older-real-kernel version, so accepting it alone
false-positives. Now `4.4.0` only counts as gVisor when /proc/version
also contains "gVisor". `*-gvisor` kernel strings remain standalone-
sufficient since no real production kernel reports them.
Adds a regression test that an Ubuntu 16.04 box reporting
`Linux version 4.4.0-1128-aws (buildd@lcy01)` is NOT classified as
a gVisor sandbox.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Add two new properties to every CLI telemetry event so we can tell
managed-sandbox traffic (Codex Cloud, Claude Code Web, etc.) apart from
real developer laptops without geolocation guesswork:
- sandbox_runtime: 'gvisor' | 'firecracker' | 'docker' | 'kvm' | 'wsl' | null
gVisor detected via kernel string ('4.19.0-gvisor' or legacy Sentry
'4.4.0') + /proc/version. Firecracker via /dev/vsock + DMI sys_vendor.
Docker reuses the existing /.dockerenv + cgroup probe.
- agent_runtime: claude_code | codex | cursor | copilot_agent | jules
| replit | devin | aider | gemini_cli | hermes | openclaw | null
Detected by the EXISTENCE of well-known vendor env vars only — values
are never read. Hermes rule keys on HERMES_QUIET=1 (set unconditionally
at hermes-agent/cli.py:50). openclaw rule keys on OPENCLAW_STATE_DIR
or OPENCLAW_CONFIG_PATH (set explicitly in the spawned child env at
openclaw/extensions/qa-matrix/src/runners/contract/scenario-runtime-cli.ts).
Drive-by cleanups required by fallow because system.ts and client.ts
fall into the audit scope of this PR:
- Extract detectWSL into platform.ts to break the system.ts ↔ agent_runtime.ts cycle.
- Refactor detectCI / getCIName into a single CI_PROVIDERS table.
- Dedupe flush / flushSync via a shared drainQueueToPayload helper.
Privacy posture unchanged: HYPERFRAMES_NO_TELEMETRY=1 still opts out;
disclosure in docs/packages/cli.mdx updated to enumerate the new fields.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
James Russo