Purpose:
    Enumerates all registered documents, returning their identifiers, classes, source paths,
    titles, and PDF/A flags.

    When to use:
    - When discovering valid `doc_id` values before calling `render` or `audit_pdf`.
    - When checking document classes (e.g. CV, paper, report, letter) registered in the workspace.

    When NOT to use:
    - Do NOT use if you only need a quick connectivity probe; use `doc_count` instead.
    - Do NOT use for raw YAML content; use the `inclusio://meta` resource instead.

    Behavioral transparency:
    Pure, read-only filesystem inspection. Reads `data/meta.yaml` without mutating any state.

    Returns:
    List of document specification dictionaries. Empty list when no manifest exists.
    

    Purpose:
    Verifies whether built PDFs satisfy PDF/UA-2, WTPDF, and PDF/A-4f triple-conformance
    accessibility and preservation standards using veraPDF.

    When to use:
    - When validating accessibility compliance of compiled PDF documents prior to publication.
    - When auditing batch PDFs under `build/` for regulatory standards (EAA, WCAG 2.2 AA).

    When NOT to use:
    - Do NOT use to generate or compile documents; use `render` and the build pipeline first.
    - Do NOT use if veraPDF is not installed or available on PATH.

    Behavioral transparency:
    Read-only audit. Shells out to veraPDF without modifying any PDF or source files.

    Returns:
    Audit report dictionary detailing summary, per-PDF results, and per-flavour passes/fails.
    

    Purpose:
    Materializes document templates into concrete source files (LaTeX, Markdown, JSON, text)
    under `build/.cache/rendered/` applying the specified build mode.

    When to use:
    - When generating LaTeX source for PDF compilation and accessibility tagging.
    - When generating Markdown or text representations for review or downstream processing.

    When NOT to use:
    - Do NOT use without discovering valid `doc_id` values first using `list_docs`.
    - Do NOT use to compile PDFs directly; this tool produces rendered sources for compilation.

    Behavioral transparency:
    Non-destructive, idempotent cache writer. Regenerates files under `build/.cache/rendered/`
    without modifying template sources or `data/meta.yaml`.

    Returns:
    Dictionary containing doc_id, format, build mode, output_path, and byte size.
    

    Purpose:
    Fast, lightweight health and connectivity probe that counts registered documents in the manifest.

    When to use:
    - When verifying server availability and project manifest readability with minimal payload size.
    - When performing initial connectivity checks before deeper inspection.

    When NOT to use:
    - Do NOT use when full metadata (doc_id, class, title) is needed; use `list_docs` instead.

    Behavioral transparency:
    Read-only, instantaneous manifest header check.