improve(development-codebase-tools): refocus code-explainer-agent on comprehension only

[wkoutre]

Summary

• Refocuses code-explainer-agent on single responsibility: code comprehension and architectural understanding only
• Removes security analysis and performance analysis sections — security-analyzer-agent and performance-analyzer-agent already exist as dedicated specialists; duplicating their logic here created confusion about which agent to use
• Adds tools (Glob, Grep, Read, Bash) and model: sonnet to frontmatter
• Rewrites description with concrete trigger phrases ("explain this code", "walk me through this file", "how does X work") for reliable agent matching
• Replaces encyclopedic 10-section output (with 30+ subsections) with 5 focused sections: Overview, Architecture & Structure, Dependencies, Key Decisions, Mental Model
• Adds explicit delegation guidance to route users to the right specialist agent

Motivation

The original file violated single responsibility by attempting security audits, performance profiling, compliance reviews, AND code explanation simultaneously. This made it redundant with security-analyzer-agent and performance-analyzer-agent, and produced over-engineered output for what is fundamentally a comprehension task.

Test plan

• Verify code-explainer-agent triggers correctly on explanation requests ("explain this file", "how does X work")
• Verify it does NOT trigger on security/performance-focused requests
• Confirm output structure is proportionate (short files get short explanations)
• Confirm delegation suggestion appears when security/performance topics arise

AI-Generated Description

Summary

• Refocuses code-explainer-agent on single responsibility: code comprehension and architectural understanding only
• Removes security analysis and performance analysis sections — security-analyzer-agent and performance-analyzer-agent already exist as dedicated specialists; duplicating their logic here created confusion about which agent to use
• Adds tools (Glob, Grep, Read, Bash) and model: sonnet to frontmatter
• Rewrites description with concrete trigger phrases ("explain this code", "walk me through this file", "how does X work") for reliable agent matching
• Replaces encyclopedic 10-section output (with 30+ subsections) with 5 focused sections: Overview, Architecture & Structure, Dependencies, Key Decisions, Mental Model
• Adds explicit delegation guidance to route users to the right specialist agent

Motivation

The original file violated single responsibility by attempting security audits, performance profiling, compliance reviews, AND code explanation simultaneously. This made it redundant with security-analyzer-agent and performance-analyzer-agent, and produced over-engineered output for what is fundamentally a comprehension task.

Changes

File	Change
packages/plugins/development-codebase-tools/agents/code-explainer.md	Rewrite from 269-line encyclopedic agent to 75-line focused comprehension specialist; add tools/model frontmatter; replace 10+ output sections with 5 focused ones; add delegation guidance for security and performance concerns
packages/plugins/development-codebase-tools/.claude-plugin/plugin.json	Bump version 2.1.1 → 2.2.0 (minor: agent enhancement)
packages/plugins/development-codebase-tools/CLAUDE.md	Update code-explainer-agent description to reflect new scope
packages/plugins/development-codebase-tools/README.md	Update code-explainer-agent description in agents table
CLAUDE.md (root)	Update development-codebase-tools version in plugin version table (2.1.1 → 2.2.0)

Test plan

• Verify code-explainer-agent triggers correctly on explanation requests ("explain this file", "how does X work")
• Verify it does NOT trigger on security/performance-focused requests
• Confirm output structure is proportionate (short files get short explanations)
• Confirm delegation suggestion appears when security/performance topics arise

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Project	Deployment	Actions	Updated (UTC)
ai-toolkit-slack-oauth-backend	Ready	Preview, Comment	Apr 14, 2026 4:01pm

[github-actions]

🤖 Claude Code Review

✅ Review complete

Summary

This PR refocuses the code-explainer-agent from a kitchen-sink analyzer (security, performance, code quality, compliance — everything) to a focused comprehension specialist that delegates security and performance concerns to their respective specialist agents. The prompt is reduced from ~270 lines to ~75 lines, and the agent description is updated across all documentation surfaces.

Changes

1. Agent prompt rewrite (code-explainer.md): Stripped security analysis, performance profiling, code quality auditing, and compliance checking. Replaced with a focused comprehension workflow (read → trace → understand → identify patterns → synthesize) and a clean output structure (Overview, Architecture & Structure, Dependencies, Key Decisions, Mental Model).
2. Frontmatter additions: Added tools: Glob, Grep, Read, Bash and model: sonnet to the agent definition.
3. Documentation updates: Updated description in CLAUDE.md, README.md, and version table in root CLAUDE.md.
4. Version bump: 2.1.1 → 2.2.0 (minor bump for backward-compatible enhancement — appropriate since this changes agent behavior without removing the agent).

Assessment

This is a well-motivated change. The old prompt was trying to do too much — security auditing, performance profiling, OWASP compliance, Big O analysis — all crammed into a "code explainer." The new version has a clear scope boundary and properly delegates specialist work to specialist agents. The output structure (Overview → Architecture → Dependencies → Key Decisions → Mental Model) is practical and well-ordered.

The version bump to 2.2.0 (minor) is appropriate per the project's semver guidelines — this is a backward-compatible enhancement to an existing agent.

No bugs, security issues, or data corruption risks identified.

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[github-actions]

🤖 Claude Code Review

Status: ⚠️ Partial (script error)
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[github-actions]

🤖 Claude Code Review

Status: ❌ Error
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[github-actions]

📚 Documentation Check ✅

Verdict: Passed

All required documentation is updated: plugin version bumped (2.1.1 → 2.2.0), CLAUDE.md, README.md, and root CLAUDE.md version table are all in sync with the code changes.

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PR #457 Documentation Check

This PR updates the code-explainer-agent in the development-codebase-tools plugin — a significant rewrite narrowing the agent's scope to comprehension/understanding and delegating security/performance concerns to specialist agents.

Checks

Check	Status	Notes
Plugin version bump	✅ PASS	2.1.1 → 2.2.0 (minor bump, appropriate for agent behavior change)
Root CLAUDE.md version table	✅ PASS	Updated to 2.2.0
Plugin CLAUDE.md	✅ PASS	code-explainer-agent description updated
Plugin README.md	✅ PASS	Agent table row updated with new description
Changelog	ℹ️ INFO	No explicit changelog entry, but not required

All documentation is consistent and properly reflects the changes made.

✨ No Documentation Updates Needed

All documentation appears to be up to date with the code changes.

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[github-actions]

📋 Review verdict: APPROVE

👆 The main review comment above is the source of truth for this PR review. It is automatically updated on each review cycle, so always refer to it for the most current feedback.

This formal review submission is for the verdict only.

Superseded by new review after PR update

[github-actions]

📋 Review verdict: APPROVE

👆 The main review comment above is the source of truth for this PR review. It is automatically updated on each review cycle, so always refer to it for the most current feedback.

This formal review submission is for the verdict only.