Long-Term Preservation (PDF/A)

Scenario

Leave behind a PDF that still opens, reads, and verifies ten years from now. In the Japanese e-bookkeeping-law context (bundling machine-readable data) or for public records, the producer puts the document onto the PDF/A vessel and has veraPDF score it; the recipient checks whether the document's structure can survive preservation (does LTV data really exist?).

Everything below is a real measurement from 2026-09-04 (pdf-verify-mcp v0.26.0 / veraPDF 1.30.0; demo invoice, the Japanese official gazette, and self-made specimens).

Cast

Actor	Role
pdf-writer	attach_file (bundle machine-readable data) → ensure_pdfa (the vessel — writes a label only)
pdf-verify	validate_conformance (veraPDF) / detect_pades_level (LTV structure observation)
pdf-trust / pdf-publish	Intake / outbound orchestration

Sequence

Prompt examples

• "Put this invoice, CSV included, into the e-bookkeeping-law preservation format" (→ attach_file + ensure_pdfa(pdfa-3b))
• "Will this contract survive ten years? Can the signature still be verified after the certificate expires?" (→ detect_pades_level + DSS check)
• "Use PDF/A-4" (→ with attachments it must be pdfa-4f — plain pdfa-4 requires every attachment to be PDF/A itself)

Measured examples

Producer side (publish-demo-invoice.pdf): catalog has Names / AF / OutputIntents. veraPDF 1.30.0 judged PDF/A-3b COMPLIANT (146/146). The same file is 106/106 under PDF/UA-1.

Recipient side (detect_pades_level, three specimens):

Specimen	Structural observation	Evidence
Gazette, 2026-08-10 issue	B-B	no signature TS, no DSS, DocTS present
selfmade-pades-lta.pdf (no CRL)	B-T	DSS present but revocationDataCoversSigner: false (dssCrlCount 0)
selfmade-pades-crl.pdf (CRL in DSS)	B-LTA	revocationDataCoversSigner: true (dssCrlCount 1)

detect_pades_level checks whether the DSS revocation data actually covers the signer certificate. Without that coverage the level stops at B-T. That is a T3 observation, not "conforms to PAdES".

Call — validate_conformance and detect_pades_level

• Measured: pdf-verify-mcp v0.26.0, veraPDF 1.30.0

{
  "file_path": "/absolute/path/to/docs/specimens/publish-demo-invoice.pdf",
  "flavour": "pdfa-3b",
  "response_format": "json"
}

{
  "engine": "verapdf",
  "flavour": "PDF/A-3b",
  "compliant": true,
  "checkedRules": 146,
  "passedRules": 146,
  "failedRules": 0
}

{
  "file_path": "/absolute/path/to/docs/specimens/selfmade-pades-crl.pdf",
  "response_format": "json"
}

{
  "levels": [
    {
      "fieldName": "Sig1",
      "level": "B-LTA",
      "normativeBasis": "T3",
      "evidence": { "hasSignatureTimestamp": true, "hasDss": true, "hasDocumentTimestamp": true },
      "ltv": { "dssCrlCount": 1, "revocationDataCoversSigner": true }
    }
  ]
}

Measured example — a file whose label and score disagree (2026-09-15, second host)

To confirm that the label ensure_pdfa writes is never read as conformance, a deliberately non-conformant file was put through the same gate (pdf-writer-mcp v0.21.0 / pdf-verify-mcp v0.26.0 / veraPDF 1.30.0; host Grok Build 1.0.30).

Step	Tool	Measured
1	create_text_pdf (English, no fontPath)	font is Helvetica (not embedded)
2	ensure_pdfa (pdfa-3b) only	declarationRisks: FONT_NOT_EMBEDDED (Helvetica); warning: CLAIMS PDF/A-3b … conformance was NOT checked
3	identify_conformance	declared pdfA: { part: "3", conformance: "B" }; notes: identifies declared conformance only
4	validate_conformance (pdfa-3b)	engine verapdf, compliant: false, 145/146; failing rule ISO 19005-3:2012 6.2.11.4.1-1 (font not embedded)

The summary written right after step 3 was: "The file claims PDF/A-3b. ensure_pdfa only added /ID, an OutputIntent and XMP pdfaid; conformance was not examined." It did not say "it is now PDF/A". The correct report is three sentences: it claims (identify) / veraPDF's verdict is non-COMPLIANT, 145/146, 6.2.11.4.1-1 (validate) / the warning says CLAIMS … NOT checked (ensure_pdfa).

Full report: eval/hosts/grok-build/reports/UC09.md (Japanese)

How to read the results

• veraPDF is the judge for PDF/A (T2): write "veraPDF judged it COMPLIANT (146/146)", never "conforms to ISO 19005"
• A PAdES level is a structural observation (T3): "the structure matches B-LTA", never "B-LTA-conformant"
• ensure_pdfa writes a label; it does not make the file meet the standard. Unembedded fonts, encryption and JavaScript are not repaired — applied to a non-conforming file it produces a PDF that lies about itself
• veraPDF may return no PDF/A result for an encrypted PDF (measured with the gazette). That check is recorded as "not performed" — never as passed

Re-run on a second host (2026-09-15, Grok Build 1.0.30)

For the request "save as PDF/A-4, keep the CSV", the flavour chosen was pdfa-4f, and veraPDF judged it COMPLIANT (109/109). detect_pades_level on the three specimens (gazette B-B / no CRL B-T / CRL in DSS B-LTA) matched the measurements above. The specimen whose label and score disagree is in the section above. Report: UC03.md (Japanese)