Verify Refactor — act101 Agent Skill

Verify Refactor

Use after editing a function to confirm the refactor preserved behavior. Composes contract, side-effect, and CFG-equivalence checks across the two versions of one function.

verify-refactor

Confirm one function's refactor is behavior-preserving by composing three Engineering-tier verification ops over a two-version comparison: git working tree vs HEAD by default, or an explicit before/after pair.

This skill verifies one function pair. For a changed set of functions with git context, use act gate via the safe-to-merge skill; its MERGE/REVIEW/BLOCK/UNKNOWN vocabulary is deliberately distinct from this skill's SAFE/REVIEW/UNSAFE/UNKNOWN.

Tools

Step	Tool	Question it answers
1	`verify_contract_preserved`	Did the public and behavioral contract (signature, effects, control, returns, guards, raises) change?
2	`verify_side_effects`	Which side effects were added or removed? Was a cleanup dropped?
3	`verify_behavioral_equivalence`	Is the control-flow shape equivalent (no new or removed branches, loops, exception paths)?

verify_behavioral_equivalence with scope:"port" is Enterprise and belongs to port-verify.

Workflow

verify_contract_preserved with target and file. A broken verdict ends the run: report the broken dimensions.
verify_side_effects. Surface dropped_cleanup: true first: a removed write or close while an allocation is kept is a likely leak.
verify_behavioral_equivalence. equivalent means the shape held; changed lists the dimensions; unknown means a grammar dimension (Go exceptions, for example) could not be judged and carries no safety claim.

Verdict

SAFE: contract preserved, no dropped cleanup, behaviorally equivalent.
REVIEW: contract preserved but effects changed, or the CFG changed in an expected way. Summarize what moved.
UNSAFE: contract broken, dropped_cleanup: true, or behavior changed unexpectedly.
UNKNOWN: any op returned unknown on an unmodeled dimension. UNKNOWN stays UNKNOWN; it never becomes SAFE.

Summary format

The verdict, the three op results in one line each, and the specific dimensions or effects that changed. Quote modeled_kinds when the verdict is UNKNOWN.