Change Analysis

Change Analysis

Run evidence-first analysis: truth, risk, next action before implementation, review, release, sync.

Input Schema

{
  "question": "required analysis question",
  "scope": "required files, diff, issue text, report path, PR number, or repo area",
  "mode": "local|github|report|ecosystem",
  "done_when": "findings are source-backed, ranked, and have explicit confidence"
}

Workflow

Codex provides this selected SKILL.md path. Resolve PLUGIN_ROOT as directory two levels above containing skill directory, then use only helpers under PLUGIN_ROOT/shared/ that are listed in package-manifest.json. Never guess cache version or fall back to source checkout.

01: Create run directory

Run create_run.py --skill change-analysis per ../../shared/helper-cli-contract.md.

02: Normalize the analysis mode

• local: code, local diff/reports, pasted text.
• github: live issue/release/repository metadata through github_read.py; use only its audited built-in view groups (gist, issue, pr, project, release, repo, ruleset, run, workflow) or explicit read-only GraphQL query for Discussions. PR collection uses collect_pr.py only. Prefer gh; use public HTTPS fallback only as final public REST fallback.
• report: .reports/** or .reports/codex/** artifact.
• ecosystem: downstream/API/dependency impact; current external claims need live web evidence. Do not invoke gh outside github_read.py.

For every github_read.py or collect_pr.py execution, apply full networked CLI approval and denial contract in ../../shared/native-skill-contract.md to complete owning command from its first attempt. The operation-specific brief is: Action and purpose: collect current GitHub analysis evidence; External capability: read-only GitHub network access; Credential behavior: gh, when used, is opaque local credential broker; Filesystem and worktree effects: write evidence only to analysis run directory, except selected PR collector may create its documented local checkout; Retry policy and safe denial outcome: stop turn on denial and use only already-available local or pasted evidence when selected mode permits it. Runtime web tools keep their own permission path and receive no shell escalation.

If mode is unsupported, explain which supplied value is invalid and list accepted modes above. If request is ambiguous, name missing source or scope decision and ask one concrete question with its supported choices or expected input format, such as a PR number/URL, issue number/URL, or local file path. Continue as local when pasted evidence supports requested analysis, stating its freshness limits; do not request mode choice that available evidence already resolves. Resume affected analysis when user supplies missing decision or evidence.

03: Capture scope and source inventory before drawing conclusions

Use python PLUGIN_ROOT/shared/collect_diff.py --help; collect working-tree into <run-directory>/baseline. Scan references separately; record failed diff collection.

Structural context (optional): for local/ecosystem scope naming Python module or symbol, probe codemap-py once: python PLUGIN_ROOT/shared/codemap_adapter.py context --category analysis [--target <qname>] --out <run-directory>/codemap-context.json. Per ../../shared/codemap-contract.md, absence/incompatibility is non-fatal — continue with evidence above. Persist result once here; step 05 specialist fan-out consumes <run-directory>/codemap-context.json, never fresh query.

04: Gather evidence with a ledger. Write <run-directory>/evidence.md with one row per claim:

| Claim | Source | Freshness | Confidence | Notes |
| --- | --- | --- | --- | --- |

Evidence rules:

• Code claims: file/line refs.
• External/current: primary sources or unavailable-live-verification caveat.
• Thread/report: distinguish facts/hypotheses.
• List duplicate/related findings; do not silently collapse.

05: Orchestrate specialist analysis when the question has independent axes

Read and apply ../../shared/specialist-orchestration.md only for broad/multi-risk PR/issue, ecosystem, or independently challenged conclusions; do not load it when narrow local fan-out would duplicate context.

Write <run-directory>/orchestration.md when fan-out is used or intentionally skipped for broad scope. Include:

• specialist axes considered
• context pack per triggered axis
• skipped axes with rationale
• consolidation plan

Routes: qa-specialist testability; web-explorer current ecosystem; scientist method; curator config/workflow drift; challenger high-impact conclusions. Use Sol-pinned solution-architect for architecture/API or security-auditor for risk only when user expressly requests Sol or selects that role; each is bounded read-only advisory artifact returned to Terra parent/session for next action and acceptance.

06: Analyze alternatives before recommending action

Required sections in <run-directory>/analysis.md:

• Question
• Scope
• Verified Facts
• Hypotheses
• Rejected Alternatives
• Findings
• Recommendations
• Gaps

07: Run the self-review check

Run git diff --check as argv command. Write its combined output to <run-directory>/review.txt and retain its exit status as review evidence; do not erase nonzero result.

08: Decide gate result

• pass: evidence-backed ranked findings, explicit gaps.
• fail: missing scope/blocking-claim evidence, stale external claim as fact, or no result artifact.

09: Run shared gates and write the validated result artifact

Follow ../../shared/helper-cli-contract.md and helper --help. Analysis-only: mark lint/format/types/tests not applicable with reasons; review needs non-empty analysis.md, self-review.md, clean diff. Write CHANGE_ANALYSIS_METADATA, validate change-analysis, promote only validated candidate.

Replace skip with command when analysis includes code changes/executable probes.

Self-Critical Gate

Before final output, answer in <run-directory>/self-review.md:

1. Which claim would be most damaging if wrong?
2. What evidence directly supports it?
3. What plausible alternative did you rule out?
4. Which facts are unverified or stale?
5. What next check would most improve confidence?

Critical conclusion without self-review cannot pass.

Fail-Fast Rules

1. Missing question or scope => fail.
2. Unsupported mode with insufficient pasted/local evidence => fail.
3. Current external claim lacks live primary-source evidence/stale-unverified caveat => fail.
4. Blocking conclusion without evidence ledger entry => fail.
5. Missing self-review for critical conclusions => fail.
6. Broad multi-axis analysis lacks orchestration evidence/skip rationale => fail.
7. Result artifact missing => fail.

Quality Gates

Required checks:

• review: evidence ledger, self-review, git diff --check when diff exists.

Optional checks:

• lint, format, types, tests: only with code changes/executable probes.

Calibration Hooks

Update calibration when routing or evidence expectations change:

• benchmark patterns: change-analysis
• behavioral cases: unsupported claims, stale-source caveats, duplicate/related-item handling, networked CLI owning-command approval

Output Contract

Before writing result candidate, follow ../../shared/final-handoff-contract.md: render and bind final-handoff.json, final.md, and final-handoff.validation.json; after both validators and promotion pass, emit final.md verbatim.

Use ../../shared/quality-gates.md.

Final chat

Final chat follows shared ordered frame. Outcome states analysis conclusion and recommended decision. Results has one ranked finding per row and exactly Finding | Impact | Decision | Evidence | Next action. Apply shared Verification, Remaining, Next steps, Confidence, and supplemental Artifact rules; remaining analysis limits include open assumptions, unavailable evidence, and next check.

Minimum artifact payload template: result-template.json.