feat: add python-property-based-testing skill

.github/workflows/ci.yml

@@ -70,6 +70,7 @@ jobs:
         run: |
           uvx --python 3.11 --from 'skills-ref==0.1.1' agentskills validate src/python-blackbox-testing
           uvx --python 3.11 --from 'skills-ref==0.1.1' agentskills validate src/python-parameterized-testing
+          uvx --python 3.11 --from 'skills-ref==0.1.1' agentskills validate src/python-property-based-testing
           uvx --python 3.11 --from 'skills-ref==0.1.1' agentskills validate src/python-test-suite-audit
           uvx --python 3.11 --from 'skills-ref==0.1.1' agentskills validate src/python-type-safety
 
@@ -136,7 +137,7 @@ jobs:
           # line after the CLI's `│    ` box-drawing indentation. A bare substring
           # match would false-pass on a renamed skill (`-v2` suffix) or on another
           # skill's description that merely mentions this name.
-          for skill in python-blackbox-testing python-parameterized-testing python-test-suite-audit python-type-safety; do
+          for skill in python-blackbox-testing python-parameterized-testing python-property-based-testing python-test-suite-audit python-type-safety; do
             if grep -Eq "^[^[:alnum:]]*${skill}[^[:alnum:]]*$" "$plain"; then
               echo "OK: $skill is listed by skills.sh discovery"
             else

CHANGELOG.md

@@ -28,6 +28,12 @@ All notable changes to this project are documented in this file. The format foll
 - Eight eval fixtures (four per skill) covering the lite profile, env
   allowlist, level choice, sandbox fallback, dependent checksums, recurrence
   without goldens, manual minimization, and rate-limit strategy.
+- `python-property-based-testing`, an independently installable Hypothesis-led skill for quantified
+  properties (round-trip, invariant, idempotence, order, differential, metamorphic) with strategy
+  design, assume budgets, settings/deadline/database recording, shrinking, and seed/replay. It ships
+  three references, eval fixtures with a depth-split near-miss against parameterized tables, and a
+  standard-library-only `plan_property_matrix.py` planner. Stateful RuleBasedStateMachine work is
+  explicitly deferred.
 
 ## [0.1.0] - 2026-09-24
 

CONTRIBUTING.md

@@ -168,6 +168,7 @@ reproducible; bump the pin deliberately and record the re-verification:
 ```bash
 uvx --python 3.11 --from 'skills-ref==0.1.1' agentskills validate src/python-blackbox-testing
 uvx --python 3.11 --from 'skills-ref==0.1.1' agentskills validate src/python-parameterized-testing
+uvx --python 3.11 --from 'skills-ref==0.1.1' agentskills validate src/python-property-based-testing
 uvx --python 3.11 --from 'skills-ref==0.1.1' agentskills validate src/python-test-suite-audit
 uvx --python 3.11 --from 'skills-ref==0.1.1' agentskills validate src/python-type-safety
 ```

README.md

@@ -20,6 +20,7 @@ to inspect, not proof that a program is correct.
 | --- | --- |
 | `python-blackbox-testing` | Testing a CLI's documented exit codes and output; characterizing a public HTTP or Python API; checking state transitions and observable side effects without coupling tests to private implementation details. |
 | `python-parameterized-testing` | Building a boundary matrix for a parser; combining fixed and generated inputs; testing Unicode and malformed data; replaying a seeded counterexample; or adding a property with an explicit oracle. |
+| `python-property-based-testing` | Proving a quantified invariant with Hypothesis strategies and shrinking; designing oracles, bounding assume/filtering, replaying a shrunken counterexample with seed and settings. |
 | `python-test-suite-audit` | Auditing an existing suite for tautological tests, weak assertions, over-mocking, private coupling, missing error paths, or order-dependent structure; producing a severity scorecard without changing code. |
 | `python-type-safety` | Adding missing annotations boundary-first; gating with mypy or pyright to zero errors; triaging error codes; recording checker divergences without chasing them. |
 
@@ -33,6 +34,9 @@ with the conventions already present in the target repository.
 - `python-parameterized-testing` for domain and property depth on logic: input matrices, boundary
   families, generated witnesses with seeds and replay, and round-trip, invariant, or metamorphic
   properties with explicit oracles.
+- `python-property-based-testing` for quantified property depth on one contract: Hypothesis
+  strategies, composites, assume budgets, shrinking, and seed/replay with an independent oracle.
+  Finite tables stay with parameterized; stateful sequences are deferred.
 - `python-test-suite-audit` for read-only suite health: grade whether existing tests detect
   faults or inflate coverage, with Critical/Major/Minor severities and confirmation by
   execution. Audit first, then use black-box or parameterized remediation without
@@ -67,6 +71,12 @@ Install the parameterized testing skill:
 npx skills add nexusnv/python-agentic-skills --skill python-parameterized-testing
 ```
 
+Install the property-based testing skill:
+
+```bash
+npx skills add nexusnv/python-agentic-skills --skill python-property-based-testing
+```
+
 Install the test suite audit skill:
 
 ```bash