fix(server): let agents use simctl and adb alongside device tools

[juliusmarminge]

The device instructions told agents never to call simctl, adb, or xcrun while the device_* tools were attached. That rule showed up in both the always-on prompt and the device_open quick start. It stopped agents from doing things agent-device can't do, like building, reading logs, or setting up Metro port forwarding.

Both texts now tell the agent to prefer the device tools and agent-device for opening and driving devices, and say the platform tools are still there for anything those don't cover. The internals doc sentence that described the prompt as forbidding raw simctl/adb now matches.

No UI changes. handlers.test.ts passes. No test checked the old wording.

Done with Claude Opus 5.5 in Claude Code.

🤖 Generated with Claude Code

---

Summary by CodeRabbit

• Documentation
  • Device guidance now recommends using the provided device tools to open and control devices, while allowing platform tools for tasks they don’t cover, such as builds, logs, and port forwarding.

[macroscopeapp]

Approvability

Verdict: Not approved

Macroscope's review found this PR not approvable — This PR changes the default instructions that guide agents during device workflows, broadening when they may use simctl, adb, and xcrun alongside the existing device tools. Although the implementation is small and isolated, changes to product defaults require human review.

^{You can add or adjust custom eligibility rules. Learn more.}

[coderabbitai]

Navigate logical layers of code changes, visualize relationships, and explore their blast radius.

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: Repository: pingdotgg/t3code/.coderabbit.yaml

Review profile: CHILL

Plan: Team

Run ID: 3edcae2b-6444-483c-8b85-6f89bbe15078

📥 Commits

Reviewing files that changed from the base of the PR and between c9a0e8a and 7a80e59.

📒 Files selected for processing (3)

• apps/server/src/mcp/toolkits/device/handlers.ts
• apps/server/src/provider/CodexDeveloperInstructions.ts
• docs/internals/devices.md

Included review availability: This review used your included allowance. Your plan provides up to 10 included reviews per hour; 9 remain after this review.

---

📝 Walkthrough

Walkthrough

Device guidance now prefers agent-device and T3 device tools for opening and driving devices. It allows platform commands for tasks those tools do not cover. The unavailable-platform reporting instruction remains.

Changes

Device Tool Guidance

Layer / File(s)	Summary
Device tool usage guidance apps/server/src/provider/CodexDeveloperInstructions.ts, apps/server/src/mcp/toolkits/device/handlers.ts, docs/internals/devices.md	The instructions prefer agent-device and T3 device tools for opening and driving devices. They allow platform commands for uncovered tasks instead of prohibiting them. The unavailable-platform reporting instruction remains.

Priority: ⬇️ Low

Estimated code review effort: 1 (Trivial) | ~4 minutes

Change: Bug fix

Merge Risk: ⚪ Minimal · up to 7a80e

The guidance consistently prioritizes device tools for opening and driving devices while allowing platform commands for tasks they do not cover. No material merge-blocking risk is evident.

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title clearly and concisely describes the main change: allowing agents to use simctl and adb alongside device tools.
Description check	✅ Passed	The description explains what changed and why, identifies the affected tools and instructions, reports test status, and states that there are no UI changes. It does not include the template checklist …
Docstring Coverage	✅ Passed	Docstring coverage is 100.00% which is sufficient. The required threshold is 80.00%. Docstring coverage is scoped to functions touched by this diff. Analyzed 1 functions across 2 files. (1 skipped: 1 …
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

✨ Finishing Touches

📝 Generate docstrings

• Commit to this branch
• Create a new PR

🧪 Generate unit tests (beta)

• Commit to this branch
• Create a new PR

---

_{Comment @coderabbitai help to get the list of available commands.}

[github-actions]

Thread transfer impact

✅ Thread transfer remains within every enforced ceiling.

Provider	Metric	Main baseline	This PR	Impact	PR ceiling
Codex	Total thread wire	13.5 KiB	13.5 KiB	−36 B (−0.3%)	15.1 KiB	✅
Codex	Thread snapshot wire	7.1 KiB	7.1 KiB	0 B (0.0%)	7.3 KiB	✅
Codex	Live turn WebSocket wire	6.5 KiB	6.4 KiB	−36 B (−0.5%)	7.8 KiB	✅
Codex	Live turn WebSocket decoded	56.3 KiB	56.2 KiB	−44 B (−0.1%)	66.4 KiB	✅
Codex	Live turn messages	10	9	−1 (−10.0%)	21	✅
Claude	Total thread wire	13.5 KiB	13.5 KiB	+9 B (+0.1%)	15.1 KiB	✅
Claude	Thread snapshot wire	7.1 KiB	7.1 KiB	0 B (0.0%)	7.3 KiB	✅
Claude	Live turn WebSocket wire	6.4 KiB	6.4 KiB	+9 B (+0.1%)	7.8 KiB	✅
Claude	Live turn WebSocket decoded	57.0 KiB	57.0 KiB	0 B (0.0%)	66.4 KiB	✅
Claude	Live turn messages	9	9	0 (0.0%)	21	✅

Baseline: c9a0e8a · PR result: 7a80e59 · Source CI: success

Scenario and decoded snapshot size

10 historical turns, 5 command tools per turn, 878.9 KiB retained MCP result per historical turn, and a 1.05 MiB retained result in the measured turn.

• Codex decoded thread snapshot: 114.0 KiB
• Claude decoded thread snapshot: 114.7 KiB

Updated in place by a trusted workflow. PR artifacts are strictly validated and never executed.