## Thinking Path
Production e2e on the merged #5790 plugin failed on every fresh lease
with "Failed to install the adapter runtime command" for a harness that
was present in the runtime image. Tracing the lease showed the first
exec resolved no pod: the exact-label fallback added during the #5790
review queries `agents.x-k8s.io/sandbox-name=<name>`, but the
kubernetes-sigs agent-sandbox controller labels pods only with
`agents.x-k8s.io/sandbox-name-hash` (see `sandboxLabel` in its
`controllers/sandbox_controller.go`) and NAMES the backing pod exactly
after the Sandbox CR. The selector matches nothing, `findPodForSandbox`
returns null, execute returns "podName could not be resolved", and
adapter-utils misreports it as a missing runtime command.
## What Changed
Between the `status.podName` read and the label fallback, try an
exact-name pod GET (`readNamespacedPod({namespace, name})`). This is
collision-free, so the original review concern (name-prefix matching
execing into a concurrent sandbox's pod) stays honored. A 404 falls
through to the existing full-name label selector for controller versions
that do set such a label. Non-404 errors propagate unchanged.
## Verification
- New unit test pins the controller reality: pod named exactly like the
sandbox, only a `sandbox-name-hash` label, no full-name label; fails
before the fix, passes after.
- Review-feedback round: the primary-path test now asserts the
exact-name GET is never called, and a new test covers non-404 error
propagation (403 rejects, no fallback). 153/153 plugin tests green, tsc
clean.
- Production-verified on our deployment: agent runs were broken on every
fresh lease before this patch and complete end-to-end after it (gVisor
sandbox pool, agent-sandbox controller v0.4.6; verified run with cost
event and agent reply on a fresh tenant).
## Risks
Low: one additional pod GET per first-exec on a fresh lease, only when
`status.podName` is unset. Non-404 errors from the GET propagate
unchanged (now test-pinned).
## Issue
No existing issue; the defect is described in full under Thinking Path
(introduced by the review-round fallback change in #5790, first hit in
production e2e on 2026-06-11).
## Model Used
Claude Fable 5 (claude-fable-5, Claude Code CLI, extended reasoning,
tool use)
## Duplicate search
Searched open and closed PRs for `findPodForSandbox`,
`sandbox-name-hash`, and pod-resolution fixes; no duplicate found.
Related parent: #5790 (introduced the fallback this PR repairs).
## Checklist
- [x] I have included a thinking path that traces from project context
to this change
- [x] I have specified the model used (with version and capability
details)
- [x] I have checked ROADMAP.md and confirmed this PR does not duplicate
planned core work
- [x] I have searched GitHub for duplicate or related PRs and linked
them above
- [x] I have either (a) linked existing issues with `Fixes: #` / `Closes
#` / `Refs #` OR (b) described the issue in-PR following the relevant
issue template
- [x] I have run tests locally and they pass
- [x] I have added or updated tests where applicable
- [x] If this change affects the UI, I have included before/after
screenshots (no UI change)
- [x] I have updated relevant documentation to reflect my changes (code
comments; no doc surface affected)
- [x] I have considered and documented any risks above
- [x] All Paperclip CI gates are green
- [x] Greptile is 5/5 with no open P2s, recommendations, or follow-ups
- [x] I will address all Greptile and reviewer comments before
requesting merge
🤖 Generated with [Claude Code](https://claude.com/claude-code)
Jannes Stubbemann
482f64e343