Add defensive bash error-handling guidance to .fullsend/AGENTS.md #47

What happened

The retro agent created issue #44 with a proposed bash snippet for the cve-bump agent definition that lacked error handling on the yarn dedupe remediation command. The code agent implemented this snippet verbatim in PR #45 commit e1b9cf5. The review agent (run 34272263019) correctly identified that if yarn dedupe itself failed (e.g., registry resolution error), execution would fall through to yarn install without surfacing the error — leaving duplicates in the lockfile, which is the exact condition the step was meant to prevent. The fix agent added || { echo "yarn dedupe failed"; exit 1; } in commit 1d88202, costing ~$4.19 and ~20 minutes for the fix + re-review cycle.

What could go better

The code agent should independently add error handling to bash commands in agent definition files, even when the source issue's proposed snippet omits it. Agent definition bash snippets are instruction templates that other agents will follow literally, so robustness is especially important — a missing error handler in an instruction template can propagate to every future agent run that follows it.

This repo's .fullsend/AGENTS.md already contains repo-specific agent guidance (skill invocation, test commands, yarn lockfile handling) but has no guidance about defensive bash practices in agent definition files. Adding such guidance would help code, fix, and retro agents produce more robust bash snippets when modifying files under .fullsend/rhdh/agents/.

Confidence: moderate. This is based on a single instance. The rework cost ($4.19) is modest, but agent definition files in this repo contain multiple bash blocks (cve-bump.md alone has several), so the guidance could prevent future occurrences of the same pattern.

Proposed change

Add the following guidance to .fullsend/AGENTS.md:

When writing or modifying bash commands in agent definition files
(`.fullsend/rhdh/agents/*.md`), ensure every command that can fail has
explicit error handling (e.g., `cmd || { echo "cmd failed"; exit 1; }`).
Agent definition bash snippets are instruction templates — other agents
will follow them literally, so missing error handlers propagate silently.

Place it after the existing yarn/dedupe guidance block, since it addresses the same class of concern (ensuring agent-generated artifacts are CI-ready).

Validation criteria

The next 3 code or fix agent PRs that modify bash snippets in .fullsend/rhdh/agents/ files should include error handling on every failable command without requiring a review-agent finding to add it. Verify by checking that review agent runs on those PRs do not flag missing error handling in bash commands.

Generated by retro agent from #45