Backfill Timing

Backfill Timing

You retrofit YAML frontmatter with pipeline timing metadata onto existing project artifacts on a WCP work item. This is for projects that completed stages before the timing system was added.

Inputs

• All artifacts on WCP work item $ARGUMENTS
• The current repository — for git commit timestamps

Before You Start

1. Locate the conventions file in the current repo root — look for CLAUDE.md, AGENTS.md, or CONVENTIONS.md (use the first one found). Read it in full.
2. Verify the work item exists by attempting to read artifacts (e.g., wcp_get_artifact($ARGUMENTS, "prd.md")).

Document-to-Stage Mapping

Step-by-Step Procedure

1. Inventory Documents

Read each known artifact by filename via wcp_get_artifact($ARGUMENTS, filename):

• prd.md
• discovery-report.md
• architecture-proposal.md
• gameplan.md
• test-coverage-matrix.md
• progress.md
• qa-plan.md

For each that returns content, check if it already has YAML frontmatter with pipeline_stage set. If so, skip it — it was created with live timing.

2. Determine Timestamps per Document

For each document that needs backfilling, try these data sources in priority order:

Source A: Git Commit Timestamps (best precision)

For progress.md, read its milestone sections. Each milestone section has a **Commit:** \SHORT_SHA`` field. For each commit SHA found:

git log -1 --format='%aI' <sha>

This gives the commit's author date in ISO 8601 format. Use this as pipeline_mN_completed_at for the corresponding milestone.

Source B: Document Header Dates (day-level precision)

Most documents have a header like > **Date:** February 5, 2026. Parse the header from the artifact content and format as YYYY-MM-DDT00:00:00-0600 (use local timezone offset from date +%z).

Use this as pipeline_completed_at.

Source C: Approval Checklist Dates

For architecture-proposal.md and gameplan.md, parse the Approval Checklist section from the artifact content. The ### Date: field contains the approval date. Parse and format as ISO 8601.

Use this as pipeline_approved_at.

Note: WCP artifacts don't have filesystem timestamps. If no other source is available (git commits, document header dates, or approval checklist dates), omit the timestamp.

3. Write Frontmatter

For each document that needs backfilling:

1. The content was already read in Step 1
2. Prepend the YAML frontmatter block to the content
3. Reattach the modified content using the type mapping below:

wcp_attach(
  id=$ARGUMENTS,
  type="<type>",
  title="<title>",
  filename="<filename>",
  content="<modified content with frontmatter>"
)

Type mapping:

Standard documents (prd.md, discovery-report.md, test-coverage-matrix.md, qa-plan.md):

---
pipeline_stage: <N>
pipeline_stage_name: "<name>"
pipeline_project: "$ARGUMENTS"
pipeline_completed_at: "<timestamp>"
pipeline_backfilled: true
pipeline_backfill_source: "<source description>"
---

Note: pipeline_started_at is omitted — it cannot be recovered from backfill sources.

Documents with approval (architecture-proposal.md, gameplan.md):

---
pipeline_stage: <N>
pipeline_stage_name: "<name>"
pipeline_project: "$ARGUMENTS"
pipeline_completed_at: "<timestamp>"
pipeline_approved_at: "<approval timestamp>"
pipeline_backfilled: true
pipeline_backfill_source: "<source description>"
---

progress.md (per-milestone timing):

---
pipeline_stage: 5
pipeline_stage_name: implementation
pipeline_project: "$ARGUMENTS"
pipeline_m1_completed_at: "<timestamp from commit>"
pipeline_m2_completed_at: "<timestamp from commit>"
pipeline_backfilled: true
pipeline_backfill_source: "git commit timestamps"
---

4. Backfill Source Descriptions

Use these descriptions for the pipeline_backfill_source field:

If multiple sources were used for different fields, use the primary source.

What NOT To Do

• Do not fabricate timestamps. If no source exists, omit the field.
• Do not overwrite existing frontmatter. Skip documents that already have pipeline_stage in their frontmatter.
• Do not modify document content below the frontmatter. Only prepend/update the YAML block.
• Do not set pipeline_started_at on backfilled documents. Start times are unrecoverable.

When You're Done

Post a completion comment:

wcp_comment(
  id=$ARGUMENTS,
  author="pipeline/backfill-timing",
  body="Timing frontmatter backfilled for [N] artifacts"
)

Tell the user:

1. Which documents were backfilled (and which were skipped)
2. What data sources were used for each document
3. Any documents where no timestamp could be determined
4. Remind them: "Backfilled documents have pipeline_backfilled: true to distinguish them from live-captured timestamps. Run /metrics $ARGUMENTS to see the computed timing data."