---
name: velcrafting/compatibility-check
source: https://app.decimal.ai/s/velcrafting-compatibility-check@1/SKILL.md
source_sha256: 840f4e1d417b
---

# Skill: api/compatibility-check

## Purpose
Determine whether an API change is:
- backward-compatible
- conditionally compatible
- breaking

And make that status explicit before shipping.

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## Inputs
- Old contract
- New contract
- Known consumers (if available)

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## Outputs
- Compatibility assessment:
  - compatible / breaking / unsafe
- Explicit list of breaking changes (if any)
- Recommendation:
  - proceed
  - version
  - block

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## Non-goals
- Modifying contracts
- Updating clients
- Implementing migrations

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## Workflow
1) Compare old vs new contract shapes.
2) Identify removed or behaviorally changed fields.
3) Assess consumer impact.
4) Emit a clear compatibility verdict.

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## Checks
- All removals and type changes enumerated
- Verdict is explicit and justified

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## Failure modes
- Missing baseline contract → block and request one.
- Ambiguous change → recommend `meta/spec-sculptor`.

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## Telemetry
Log:
- skill: `api/compatibility-check`
- verdict
- affected_consumers
- outcome