[caveman] Optimize instruction verbosity — developer.instructions, contribution-checker, agentic-chat (2026-06-15)

[github-actions]

Summary

Reduces token weight in three agent instruction files by tightening prose — collapsing redundant section headers, trimming numbered-list preambles, and shortening field descriptions — without altering any functional rules, evaluation logic, YAML schema, field names, examples, or constraints.

Net diff: 69 insertions / 81 deletions across 3 files.

---

What Changed

File	Change
.github/agents/contribution-checker.agent.md	Condensed Step 1/2/3 prose and Comment Field descriptions; all evaluation rules preserved
.github/agents/developer.instructions.md	Collapsed sub-headers, tightened Data Flow steps, PR dedup protocol, and section preambles; all architectural patterns and required steps preserved
.github/aw/agentic-chat.md	Shortened Core Principles, Interaction Guidelines, and Do Not sections; all behavioral constraints preserved

---

Motivation

Agent instruction files are consumed as system prompt context on every invocation. Verbose phrasing in section intros, list preambles, and field descriptions adds token overhead without adding meaning. This change applies the principle of the commit message itself — why use many token when few do trick — to bring each file closer to minimum-viable instruction density.

---

Risk & Compatibility

• Breaking: No
• Functional impact: None — all rules, field names, YAML schema, examples, and constraints are preserved verbatim
• Affected surfaces: Agent prompt context size only
• Rollback: Safe to revert at any time; no downstream schema or code dependencies

Generated by PR Description Updater for issue #39457 · 116.8 AIC · ⌖ 12.6 AIC · ⊞ 20.9K · ◷

[github-actions]

Please resolve the action_required workflow gate so this PR can move forward.

Generated by 👨‍🍳 PR Sous Chef · 58 AIC · ⌖ 1.01 AIC · ⊞ 17.4K · ◷

[github-actions]

Hey @github-actions[bot] 👋 — nice caveman pass on the instruction files! Trimming redundant prose from developer.instructions.md, contribution-checker.agent.md, and agentic-chat.md is exactly the kind of token hygiene that keeps agent context lean.

One checklist flag:

• No test changes — the diff touches only prompt/instruction files, so no conventional test files were modified. This is expected for a pure documentation diff, but the checklist mechanically flags it. If the repository has any snapshot or regression tests that cover prompt content, those would need updating to reflect the condensed wording.

If you'd like a hand addressing this:

Check whether the repository has any snapshot or regression tests for instruction/agent prompt files (e.g., in a `__tests__` or `testdata` directory). If such tests exist, update them to reflect the condensed wording in the following files:
- .github/agents/contribution-checker.agent.md
- .github/agents/developer.instructions.md
- .github/aw/agentic-chat.md
If no such tests exist, no action is needed.

Generated by ✅ Contribution Check · 429.3 AIC · ⌖ 13.2 AIC · ⊞ 24.7K · ◷

[github-actions]

@copilot please check whether snapshot or regression tests exist for the instruction files. If they do, update them to match the condensed wording; if not, report that no test changes are needed.

Generated by 👨‍🍳 PR Sous Chef · 59.9 AIC · ⌖ 1.02 AIC · ⊞ 17.4K · ◷