AI-Powered Technical Documentation

September 16, 2024

Technical documentation is essential but often neglected. AI assistance is changing the economics—generating first drafts, keeping docs synchronized with code, and answering documentation queries. The goal isn’t to replace technical writers but to reduce the friction of documentation.

Here’s how to use AI for technical documentation.

Documentation Challenges

Why Documentation Falls Behind

documentation_challenges:
  creation:
    - Takes time away from coding
    - Requires different skills
    - Not prioritized
    - Hard to start from blank page

  maintenance:
    - Code changes, docs don't
    - No automated sync
    - Stale docs worse than none
    - Who owns updates?

  discovery:
    - Docs exist but unfindable
    - Search is poor
    - Wrong information found

AI Documentation Tools

Code-to-Documentation

class DocGenerator:
    """Generate documentation from code."""

    async def generate_function_doc(
        self,
        code: str,
        style: str = "google"
    ) -> str:
        return await self.llm.generate(
            prompt=f"""Generate {style}-style documentation for this function.

Include:
- Brief description
- Args with types and descriptions
- Returns description
- Raises (if applicable)
- Example usage

Function:
```python
{code}

Documentation:""" )

async def generate_module_doc(
    self,
    module_code: str
) -> str:
    return await self.llm.generate(
        prompt=f"""Generate module-level documentation for this Python module.

Include:

Module:

{module_code}

Module documentation:""" )

async def generate_api_doc(
    self,
    endpoint_code: str
) -> str:
    return await self.llm.generate(
        prompt=f"""Generate API documentation for this endpoint.

Include:

Endpoint code:

{endpoint_code}

API documentation (OpenAPI-compatible):""" )


### Documentation Updater

```python
class DocUpdater:
    """Keep documentation synchronized with code."""

    async def detect_staleness(
        self,
        code: str,
        docs: str
    ) -> StalenessReport:
        result = await self.llm.generate(
            prompt=f"""Compare this code with its documentation.
Identify any inconsistencies or outdated information.

Code:

{code}


Documentation:

{docs}


List each inconsistency:
- What the docs say
- What the code does
- Severity (high/medium/low)
"""
        )
        return StalenessReport.parse(result)

    async def update_docs(
        self,
        code: str,
        current_docs: str
    ) -> str:
        report = await self.detect_staleness(code, current_docs)

        if not report.inconsistencies:
            return current_docs

        return await self.llm.generate(
            prompt=f"""Update this documentation to match the code.

Current documentation:

{current_docs}


Issues found:
{report.format_issues()}

Updated code:

{code}


Write updated documentation that fixes these issues:"""
        )

Documentation Q&A

class DocQA:
    """Answer questions using documentation."""

    def __init__(self, vector_store, llm):
        self.vector_store = vector_store
        self.llm = llm

    async def index_documentation(self, docs_path: str):
        """Index documentation for search."""
        docs = await self._load_docs(docs_path)

        for doc in docs:
            chunks = self._chunk_document(doc)
            embeddings = await self._embed(chunks)

            for chunk, embedding in zip(chunks, embeddings):
                await self.vector_store.insert(
                    text=chunk.text,
                    embedding=embedding,
                    metadata={
                        "source": doc.path,
                        "section": chunk.section
                    }
                )

    async def answer_question(
        self,
        question: str,
        top_k: int = 5
    ) -> Answer:
        # Search relevant docs
        relevant_docs = await self.vector_store.search(
            query=question,
            top_k=top_k
        )

        # Generate answer
        answer = await self.llm.generate(
            prompt=f"""Answer this question using the documentation below.

Question: {question}

Relevant documentation:
{self._format_docs(relevant_docs)}

If the answer isn't in the documentation, say so.

Answer:"""
        )

        return Answer(
            text=answer,
            sources=[doc.metadata["source"] for doc in relevant_docs]
        )

Workflow Integration

Pre-commit Documentation Check

# .pre-commit-config.yaml
repos:
  - repo: local
    hooks:
      - id: doc-check
        name: Documentation Check
        entry: python scripts/check_docs.py
        language: python
        files: \.(py|ts|go)$
# scripts/check_docs.py
async def check_documentation(files: list[str]) -> CheckResult:
    issues = []

    for file_path in files:
        code = read_file(file_path)
        doc_path = get_doc_path(file_path)

        if not exists(doc_path):
            issues.append(Issue(
                file=file_path,
                type="missing_docs",
                message="No documentation found"
            ))
            continue

        docs = read_file(doc_path)
        staleness = await doc_updater.detect_staleness(code, docs)

        if staleness.has_high_severity:
            issues.append(Issue(
                file=file_path,
                type="stale_docs",
                message=staleness.summary
            ))

    return CheckResult(issues=issues, passed=len(issues) == 0)

CI Documentation Generation

# .github/workflows/docs.yml
name: Documentation
on:
  push:
    branches: [main]

jobs:
  generate-docs:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4

      - name: Generate API Docs
        run: python scripts/generate_api_docs.py

      - name: Check for Changes
        id: check
        run: |
          if git diff --quiet docs/; then
            echo "changed=false" >> $GITHUB_OUTPUT
          else
            echo "changed=true" >> $GITHUB_OUTPUT
          fi

      - name: Create PR
        if: steps.check.outputs.changed == 'true'
        run: |
          git checkout -b docs/auto-update
          git add docs/
          git commit -m "Auto-update documentation"
          gh pr create --title "Update documentation" --body "Automated documentation update"

Best Practices

ai_documentation_practices:
  generation:
    - AI generates first draft
    - Human reviews and edits
    - Version control everything
    - Track AI vs human contributions

  maintenance:
    - Automate staleness detection
    - Update docs in same PR as code
    - Regular sync jobs

  quality:
    - Define documentation standards
    - Use consistent style
    - Include examples
    - Test code snippets

Key Takeaways

Documentation doesn’t have to lag behind. AI helps close the gap.