Instructor is a library that helps applications obtain structured, validated data from language models using Pydantic models. It is for developers building LLM features such as data extraction across different model providers, and the catalogue entries add usage rules and instructions.
Getting it into your agent
One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.
git clone --depth 1 https://github.com/567-labs/instructorWrote this? Show the measurements
A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.
[](https://agentmods.dev/rules/567-labs/instructor/documentation-sync)<a href="https://agentmods.dev/rules/567-labs/instructor/documentation-sync"><img src="https://agentmods.dev/badge/rules/567-labs/instructor/documentation-sync/github.svg" alt="Measured on agentmods" height="20"></a>Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.
<a href="https://agentmods.dev/rules/567-labs/instructor/documentation-sync"><img src="https://agentmods.dev/badge/rules/567-labs/instructor/documentation-sync.svg" alt="Reviewed on agentmods" width="80" height="20"></a>What it costs to keep this loaded
Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5.1 | $0.00249 | $0.00249 |
| Opus 5.5 | $0.00100 | $0.00100 |
| Sonnet 5.5 | $0.00050 | $0.00050 |
| Haiku 4.5 | $0.00025 | $0.00025 |
Grade A, and why
documentation-sync scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 1mo ago.
A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.
Nothing flagged
None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.
What it actually says
-
When making code changes:
- Update related documentation files to reflect the changes
- Check docstrings and type hints are up to date
- Update any example code in markdown files
- Review README.md if the changes affect installation or usage
-
When creating new markdown files:
- Add the file to mkdocs.yml under the appropriate section
- Follow the existing hierarchy and indentation
- Use descriptive nav titles
- Example:
nav: - Home: index.md - Guides: - Getting Started: guides/getting-started.md - Your New File: guides/your-new-file.md
-
For API documentation:
- Ensure new functions/classes are documented
- Include type hints and docstrings
- Add usage examples
- Update API reference docs if auto-generated
-
Documentation Quality:
- Write at grade 10 reading level (see simple-language.mdc)
- Include working code examples
- Add links to related documentation
- Use consistent formatting and style
What this file has done since we first saw it
Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.
- 1mo ago First seen · 36 lines · 249 tokens per session scan A dc7fc3a9e995
documentation-sync is a cursor rule published in the GitHub repository 567-labs/instructor (14,028 stars, last pushed 3d ago), licensed MIT. It adds 249 tokens to every session, about $0.0010 per session on Opus 5.5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.
Other cursor rules, from other repositories
backend-rules
A set of rules for developing backend services with FastAPI, a Python framework for building web APIs.
mempalace-recall-always
Always-on MemPalace recall — search the palace before answering about past work, people, projects, or prior decisions.
python
Python best practices and patterns for modern software development with Flask and SQLite.
django
Definitive guidelines for writing maintainable, performant, and secure Django applications, emphasizing modern best practices, clear code organization, and efficient patterns.
rich
Definitive guidelines for building robust, maintainable, and visually appealing Python CLI applications using the rich library.
api-tester
Expert API testing specialist focused on comprehensive API validation, performance testing, and quality assurance across all systems and third-party integrations.