[posthog]

Problem

Rust contributors wait for dependency-cache setup before CI can report formatting errors.

Why: Formatting needs rustfmt, so cache setup delays feedback without helping the check.

Changes

• Run the unchanged formatting check immediately after Rust installation. Formatting failures skip cache setup; passing runs keep every check.

Before:

flowchart LR
    A[Install Rust] --> B[Cache setup] --> C[Check format]
    classDef phBlue fill:#1d4aff,stroke:#1d4aff,color:#fff;
    class A,B,C phBlue;

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After:

flowchart LR
    A[Install Rust] --> C[Check format] --> B[Cache setup]
    classDef phBlue fill:#1d4aff,stroke:#1d4aff,color:#fff;
    class A,B,C phBlue;

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How did you test this code?

• Workflow lint, actionlint, scenario planning, and structural comparison of all steps.
• Post-merge: verify formatting failures skip both caches and passing runs reach clippy. Fleet savings remain unmeasured.

Test rationale: Only step order changes; no new test is needed. The Rust build was not run locally.

Release status

• No feature flag controls this change

Docs update

• None.

🤖 Agent context

Autonomy: Fully autonomous

Agent: Codex, GPT-6 (runtime model identifier unavailable)

Skills: /authoring-ci-workflows, /reducing-ci-costs, /verifying-changes, /running-ci-preflight, /writing-pr-descriptions

More context for AI agents

• Session: Scout context. This change does not implement the cache-size experiment.
• Decisions: Open-PR searches found no matching Rust formatting fix. Tasks search timed out.
• Follow-ups: Compare formatting-failure exposure and complete-job durations after merge. No cash savings claimed.
• Read closely: Formatting runs after rustfmt installation and before cache setup.

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Created with PostHog Desktop

[trunk-io]

😎 Merged successfully - details.

[posthog]

PostHog Review · Standard · reviewed bcd4676: no findings.

[github-actions]

🤖 CI report

✅ Trunk lane — non-backend lane

This PR is assigned to the non-backend lane. It does not run backend Python tests and may merge in parallel with PRs in other lanes.

[parameterai]

Risk: No findings

The change moves the cargo fmt -- --check step in the CI Rust job from after cache setup to before it, so formatting failures are reported faster and skip cache work. No security-relevant surface is added or altered: the step runs in the same job, runner, permissions, and checkout as before, and touches no secrets, tokens, or attacker-controlled inputs.

_{Sentinel reviewed bcd4676 · Review settings}

[posthog]

Robot: QA Swarm review complete.

Verdict: APPROVE _{(round 1 @ bcd4676)}

No findings. The format check runs after Rust installation and before cache setup. Its prerequisites and command stay the same.

Key findings

None.

Convergence

No additional review was needed.

Reviewer summaries

Reviewer	Assessment
Router (gpt-6-luna)	Low risk. High confidence. No delegation.

Automated review by QA Swarm.

[stamphog]

stamphog does not review bot-authored pull requests, so the trigger label has been removed. This change needs a human reviewer.

[deployment-status-posthog]

Deploy status

Environment	Status	Deployed At	Workflow
dev	✅ Deployed	2026-11-06 15:25 UTC	Run
prod-us	✅ Deployed	2026-11-06 15:42 UTC	Run
prod-eu	✅ Deployed	2026-11-06 15:37 UTC	Run