behavior-contract SKILL.md skillA
behavior-contract from a5c-ai/babysitter is an agent skill: a SKILL.md folder an AI agent loads when a task calls for it.
mdr add a5c-ai/babysitter/behavior-contract@v1.0.0Pins v1.0.0 in mdr.lock. Pin the fingerprint instead.
- Audit grade
- A, 17 of 17 checks passed
- Kind
- SKILL.md skill
- Repository
- a5c-ai/babysitter
- Path
library/methodologies/pilot-shell/skills/behavior-contract/SKILL.md- Versions recorded
- 5
- Latest version
- v1.0.0, committed Jun 1, 2026
- First version recorded
- Mar 25, 2026
- Size
- 2,241 bytes
- Repository stars
- 1,896
- License
- MIT
Bug condition/postcondition formalization as testable Behavior Contracts. Defines invariants that must be preserved across fixes.
Collected from public GitHub. Every version is saved exactly as it was and never changes. Install it at an exact version with the mdr tool, and every file is checked before it reaches your agent. The main file is checked against the SHA-256 fingerprint recorded here, and the others against the fingerprints GitHub keeps for its source commit. The automatic checks below grade the latest version, and the same checks always give the same file the same grade.
What the file says
- "Positive amounts still process correctly"
- "Negative amounts still throw `InvalidAmountError`"
- "Receipt format remains unchanged for all amount types"
## Contract Document Template
```markdown
# Behavior Contract: [Bug Title]
## Bug Condition
[Precise description of triggering conditions]
## Postcondition
[Expected correct behavior after fix]
## Invariants
- [ ] Invariant 1: [existing behavior to preserve]
- [ ] Invariant 2: [existing behavior to preserve]
## Testable Assertions
1. `expect(processPayment(0)).toEqual({ amount: 0, status: 'completed' })`
2. `expect(processPayment(100)).toEqual({ amount: 100, status: 'completed' })`
3. `expect(() => processPayment(-1)).toThrow(InvalidAmountError)`
```
## Usage in Bugfix Workflow
1. Bug analysis identifies root cause at file:line
2. This skill formalizes the contract from the analysis
3. tdd-enforcer writes failing test from Bug Condition
4. tdd-enforcer writes preservation tests from Invariants
5. Minimal fix applied, contract auditedRead the whole file at its exact version.
How to install
mdr add a5c-ai/babysitter/behavior-contract@sha256:fbdb583090423df5The line at the top of this page pins the label v1.0.0, which is what most people want. This one pins the sha256 fingerprint of the contents instead, so it survives a label being moved. Either way the exact version is written to mdr.lock, and mdr install downloads and checks those contents again, so it installs them exactly or stops with an error.
[](https://markdownregistry.com/a/art_vyfycgtzw2pj7hit)
4 badge image fetches in 30 days. What the badge shows.
Versions
The registry has recorded 5 versions of this file, between Mar 25, 2026 and Jun 1, 2026, about one every 17 days.
| version | committed | commit | size | audit | |
|---|---|---|---|---|---|
| v1.0.0 latest | 2026-06-01 | da7723a | 2,241 B | A | view · diff |
| v1.0.0 | 2026-05-07 | 9f5be95 | 2,295 B | A | view · diff |
| git:20260507.8dfdcb4 | 2026-05-07 | 8dfdcb4 | 2,290 B | C | view · diff |
| v1.0.0 | 2026-05-07 | 56f011d | 2,467 B | A | view · diff |
| v1.0.0 | 2026-03-25 | a6b3a88 | 2,348 B | A | view |
Audit of the latest version
- pass: Frontmatter block present
- pass: Frontmatter declares a name
- pass: Frontmatter declares a description
- pass: Size between 200 bytes and 200 KB (2241 bytes)
- pass: No zero-width or bidi control characters
- pass: No instruction hidden inside an HTML comment
- pass: No link to an exfiltration or paste host
- pass: No credential-shaped string
- pass: No instruction to send local credentials anywhere
- pass: No text hidden with inline styles
- pass: No prompt-injection phrasing
- pass: No curl or wget piped into a shell
- pass: No recursive delete of root, home or parent
- pass: No instruction to read or print local credentials
- pass: No base64 blob over 200 characters
- pass: No link to a raw IP address
- pass: No script tag
Source
a5c-ai/babysitter · 1,896 stars · license MIT · pushed 2026-11-01 · branch main
API
GET https://markdownregistry.com/api/v1/artifacts/art_vyfycgtzw2pj7hit GET https://markdownregistry.com/api/v1/resolve?ref=a5c-ai/babysitter/behavior-contract GET https://markdownregistry.com/api/v1/blob/fbdb583090423df5b78710318db9c44c3301b0bd28a53ae78d9722f40de924c9
Your AI assistant does the legwork. You hear about the deals worth your word. Hand yours the standing instructions at modelranch.com and it joins the network that reads files like this one.
Guides: the SKILL.md format and its required fields · what to check before you install a skill · how to pin a skill to an exact version · where to find agent skills · keeping a team on the same skills · which agent file does what.