Reviewing and Updating Skills

When to review

Review the relevant skills and instructions after any work that changes:

• Public API surface — new methods, renamed parameters, changed signatures
• Build or test infrastructure — new solution files, changed filters, new TFMs
• Architecture — new projects, moved files, changed conventions
• Code generation — new keywords, changed handler behaviour, new CLI options
• Documentation pipeline — new build steps, changed tool behaviour

The rule is simple: if the code changed, check whether the instructions still match.

What to check

For each skill touched by your changes, verify these in order:

1. Code examples compile and are accurate

Every code block in a skill should use real types, real method signatures, and real parameter names from the current codebase. The most common failure mode is fabricated or stale API usage — a method that was renamed, a parameter that was added, or a constructor whose signature changed.

To verify, pick each code example and check the actual source:

# Find the real signature
grep -rn "public.*MethodName" src/

Common drift patterns:

• Constructor gains a new required parameter (skill example silently omits it)
• Method renamed but skill still uses the old name
• Enum values or constants changed
• File paths moved (e.g., Common/src/ vs src/Common/)

2. Numeric values and thresholds match source

When a skill states a specific number (priority value, buffer threshold, step count, character limit), verify it against the source constant or definition. These drift silently when someone changes a constant without updating the documentation.

3. Scope boundaries are still correct

Check the USE FOR / DO NOT USE FOR fields in the YAML frontmatter. After adding a new feature or project, an existing skill's scope may need updating — either to include the new area or to explicitly redirect to a new skill.

4. Cross-references point to the right places

Each skill's ## Cross-References section should link to skills that still exist and still cover the referenced topic. If a skill was renamed, split, or merged, update all inbound references.

5. No duplication with main instructions

The main copilot-instructions.md should contain brief summaries with cross-references to skills for depth. If you find the same detailed content in both places, condense the main instructions copy to a summary and cross-reference.

Adding a new skill

When a new area of the codebase deserves its own skill:

1. Create the directory and file: .github/skills/<name>/SKILL.md
2. Write the YAML frontmatter with name, description, USE FOR, and DO NOT USE FOR
3. Structure the content: overview → code examples → configuration tables → common pitfalls → cross-references
4. Add cross-references from related skills back to the new one
5. Update the skill inventory table in copilot-instructions.md
6. Update the code sample catalog:

   .\docs\update-code-sample-catalog.ps1 -UpdateFile .github/skills/<name>/SKILL.md
   

A skill earns its place when the assistant repeatedly struggles with a specific area, not when an area merely exists.

Root-causing trigger failures

When a skill or instruction existed but you did not follow it, treat that as a defect in the instructions — not just a one-off mistake. The instruction failed to trigger at the right moment, and the fix is to understand why and close the gap.

Ask these questions:

1. Was the instruction framed for the wrong trigger? An instruction that says "when you edit a documentation file" may not fire when the task is "fix the CI build." If the instruction applies in both situations, rewrite it to cover both entry points.
2. Was the instruction buried inside a larger workflow? A critical step hidden as step 5 of a 5-step process gets skipped when you jump to the end. Promote it to a standalone gate with its own heading.
3. Did the instruction assume proactive compliance? Instructions that only describe the happy path ("do X when you change Y") need a reactive counterpart ("if you forgot to do X, here is how to recover — and it still requires doing X").
4. Did multi-turn conversation obscure the trigger? When changes accumulate across many conversation turns before a commit, per-edit triggers get lost. Anchor the instruction to the commit point instead, since that is where all changes converge regardless of how they were made.

After root-causing, update the instruction to close the gap — then verify the updated instruction would have caught the original failure.

Running a full review

For a periodic audit of all skills (e.g., after a major release):

1. List all skills and check each against the current source
2. Use parallel explore agents to verify 4-5 skills each — look for fabricated APIs, wrong parameters, stale paths, missing examples
3. Cross-check findings against source code before fixing — review agents produce false positives (they may flag correct code as wrong)
4. Track findings in a structured format (SQL table or similar) with severity and status
5. Fix in priority order: critical inaccuracies → missing examples → duplication → cosmetic

Common false positives

Review agents frequently flag things that are actually correct:

• Generated type APIs that don't appear in hand-written source (they're emitted by the code generator)
• Methods found only via generic type inference (the agent's grep misses them)
• Shared source files in src-v4/ that are referenced by V5 projects via project references

Always verify against the actual source before changing a skill.

Design principles for skill content

These principles keep skills effective as AI context:

• Code-first — every skill should have at least one copy-paste-ready code example with real syntax
• Concrete over abstract — real file paths, real type names, real method signatures
• Self-contained sections — each section should make sense without reading the whole skill
• Tables for reference data — configuration options, threshold values, priority levels
• Pitfalls earn their place — only document pitfalls that have actually caused problems

Cross-References

• For verifying code samples in documentation, see the "Documentation Code Sample Verification" section in copilot-instructions.md
• For the code sample catalog tools, see docs/CodeSampleCatalog.md

Source: corvus-dotnet/Corvus.JsonSchema — distributed by TomeVault.