[earakely-scale]

What and why

start_computer_recording on an env whose card declares no recording failed with KeyError: 'max_duration_s'. So did end_computer_recording and the teardown's end_open_recordings. That covers a child env such as a website browser without a recorder, or a child the card doesn't list at all. The grant was built from the card's recording params before anything checked the card had any, so the error named a missing key, not the missing capability.

_grant now raises EnvCapabilityUnsupported, the error DeployedEnv.invoke already raises when a card doesn't offer a method. The entry records, for example: EnvCapabilityUnsupported: env 'shop' child env 'website-browser' does not offer 'start' on …computer-recording/v1.

Seen on 10-30 while gating the Playwright MCP browser's promotion (FD-4658). Dev's first website browser has no recorder, so its gate run read recording failed: KeyError: 'max_duration_s'.

How it was tested

• Unit: tst/unit/task_step/computer_recording_test.py passes, 20 tests.
  • A new test starts a recording of a child env whose card declares no recording, and of a child the card doesn't list. Each fails the start with EnvCapabilityUnsupported, naming the child, and calls nothing on the env.
  • The existing test for a start without a child env expected the KeyError text. It now expects the same error on the env's own card.
• Wider tiers: tst/unit/task_step and tst/unit/env pass, 3,593 tests. The new import (agent_env.env.env into the recording steps) imports cleanly from agent_env, the task-step registry and the CLI.

🤖 Generated with Claude Code

Confidence Score: 5/5

The PR appears safe to merge.

Summary

The PR reports EnvCapabilityUnsupported instead of a missing-key error when an env or child card declares no recording.

• Computer recording reports when an environment does not offer it.

_{Reviews (1) · Last reviewed commit: "fix(computer): a recording of an env tha..." · Reviewed by Greptile}