fix: Copilot CLI triage command rejected with 'Invalid command format'

[don-petry]

Parent issue

#145

Problem

When the session fell back to the Copilot engine for ContentTwin/pull/72, the triage step immediately failed:

error: Invalid command format.
Did you mean: copilot -i "suggest -p # Tier 1: Triage..."

The copilot CLI rejected the command that review-one-pr.sh issued during the triage tier. This indicates one or both of:

• The CLI invocation syntax used by the script no longer matches the installed CLI version (flags / subcommand changed).
• The prompt is being passed in a way the CLI rejects (e.g., positional arg vs --prompt flag, unescaped characters, length).

Because the CLI exited non-zero with this message, the rate-limit detector (see #147) classified it as a rate limit and aborted the entire session, skipping 18 PRs.

Acceptance criteria

1. Root cause confirmed: identify the exact copilot CLI invocation in review-one-pr.sh (and any shared helper) that produces the format error, and document the correct invocation for the installed CLI version.
2. Invocation fixed: the corrected command is applied and manually verified to succeed locally against a test prompt.
3. Version pinned or detected: either pin the CLI version in the workflow's setup step, or add a version-check that emits a clear error when the installed CLI is below the minimum supported version.
4. Smoke test step: add a lightweight copilot CLI smoke test (e.g., copilot --version and a one-liner prompt) as a pre-flight step so format errors surface as a clear setup failure rather than a mid-run rate-limit false-positive.
5. The triage tier completes successfully against a real low-risk PR on the Copilot engine.

Expected tests

• Unit (shellcheck / bats): the helper that builds the copilot CLI invocation string is tested with edge-case prompts (long prompt, prompts with quotes/newlines) to confirm no format errors.
• Integration (dry-run): a dry-run workflow step runs the fixed Copilot triage command and asserts exit code 0.
• Integration: a full end-to-end review of a known low-risk PR succeeds on the Copilot engine without format errors.

[don-petry]

Claude finished @don-petry's task in 22m 25s —— View job • claude/issue-147-20260512-1802

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Fix implemented for Issue #147

Root cause: scripts/engine.sh invoked gh copilot suggest -p "$(cat "$prompt_file")" in three places (run_triage, run_agentic, run_duck). The -p flag is not valid syntax in the modern gh copilot built-in, producing error: Invalid command format. Additionally, gh copilot suggest is a shell-command suggestion tool — it can't handle multi-thousand-line PR prompts or return structured JSON. The resulting non-zero exit was misclassified by the rate-limit detector, aborting the review session.

Fix applied: Replaced all three copilot invocations with a new copilot_chat helper that calls the GitHub Models REST API (https://models.github.ai/inference/chat/completions) via curl. Uses python3 for safe JSON encoding (handles # headings, newlines, quotes, large diffs), and the endpoint is stable against gh CLI version changes.

• Read CLAUDE.md and understand repo structure
• Find review-one-pr.sh / identify the copilot CLI invocation — in scripts/engine.sh (3 places)
• Diagnose root cause — -p flag invalid; gh copilot suggest wrong tool for PR review
• Add copilot_chat helper using GitHub Models REST API to scripts/engine.sh
• Fix run_triage / run_agentic / run_duck copilot cases to use copilot_chat
• Write $OUTPUT_FILE in run_agentic/run_duck copilot cases so deep-review/audit callers find JSON
• Rate-limit detection: HTTP 429 echoed to stdout so is_rate_limited() fires correctly
• Scope COPILOT_API_MODEL export to the copilot engine only (self-review fix)
• Add copilot pre-flight smoke test to scripts/review-batch.sh
• Add unit tests for copilot payload builder (tests/test_copilot_chat.sh — 9 tests covering quotes, newlines, # headings, large diffs, Unicode, backslashes, custom model names)
• Commit and push changes
• Created PR, self-reviewed, tagged code owners

PR

petry-projects/.github-private#151

What was NOT done

• Workflow smoke test step in .github/workflows/pr-review.yml — the GitHub App token does not have workflows write permission, so changes to workflow files cannot be pushed. The equivalent pre-flight check was added to scripts/review-batch.sh instead, which runs at the start of every batch when REVIEW_ENGINE=copilot.
• End-to-end test against a live PR on the Copilot engine — requires a real COPILOT_GITHUB_TOKEN with GitHub Models access.
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