## Demo
Proves the new backfill.py runner works and that running it actually landed Q3'25 (Jul–Sep) Anthropic token usage into core_finance.ai_spend_claude_token_usage — without disturbing any existing rows. All output below is real, captured from running the changed code directly via the runner's own CLI (no HTTP layer).
Pipeline — Q3'25 backfill executed (backfill --start-month 2025-07 --end-month 2025-09 --execute, run locally 2026-06-21)
Each month invokes the existing handler.handler with an end-exclusive window:
MONTH 2025-07 done: fetched=3291 deleted=0 inserted=3291MONTH 2025-08 done: fetched=3541 deleted=0 inserted=3541
MONTH 2025-09 done: fetched=3907 deleted=0 inserted=3907
Backfill execute finished (exit_code=0).
deleted=0 across all months = clean inserts (no pre-existing Q3 rows). 10,739 rows total.
Data — before vs after (backfill verify, read-only)
| Check | Before | After |
|---|---|---|
| MIN(report_date) | 2025-10-01 | 2025-07-01 |
| Total rows | 89,842 | 100,581 (+10,739) |
| Q3'25 rows [2025-07-01, 2025-09-30] | 0 | 10,739 |
New Q3 months vs already-billed cost-reports actuals (magnitude sanity check):
2025-07 3291 rows list-price $52,592 | cost-reports actual $43,078 (1.22x)2025-08 3541 rows list-price $55,467 | cost-reports actual $48,593 (1.14x)
2025-09 3907 rows list-price $87,212 | cost-reports actual $82,639 (1.06x)
List-price slightly above billed is expected (list price excludes negotiated/committed-use discounts — exactly the gap the Klair "Reconciled Cost" line reconciles); same order of magnitude. ✅
Runner safety — dry-run is the default + unit tests
Dry-run (no --execute) writes nothing and shows the exact scope:
# DRY-RUN — NO HANDLER CALLS, NO ANTHROPIC FETCH, NO DB WRITESWOULD process 2025-07 : start_date=2025-07-01 end_date=2025-08-01 (end exclusive) | BUs=ALL
WOULD process 2025-08 : start_date=2025-08-01 end_date=2025-09-01 (end exclusive) | BUs=ALL
WOULD process 2025-09 : start_date=2025-09-01 end_date=2025-10-01 (end exclusive) | BUs=ALL
$ uv run pytest tests/test_backfill.py -q22 passed in 0.14s
Most at risk from this change — checked and held:
1. No regression to existing Oct'25→Jun'26 rows (the --execute path writes to the prod table). The before/after verify shows every existing month is byte-identical — counts *and* cost sums unchanged, e.g. 2025-10 = 4,522 / $81,562.48 and 2026-05 = 17,246 / $827,028.32 in both runs. The idempotent per-(bu, report_date) delete-insert touched nothing outside Q3.
2. Month-window boundaries (off-by-one / inclusive end). Unit tests assert [first-of-month, first-of-next-month) exclusive windows incl. year rollover (Dec→Jan); Sep correctly maps to 2025-09-01 → 2025-10-01.
3. Scope creep beyond Q3. Both the dry-run plan and the execute log show exactly the three Q3 months; the optional Dec'24→Jun'25 extension was not run.
---
## Summary
Operational backfill for the Claude token-spend pipeline. The Lambda handler is already date-parameterized (params.start_date / params.end_date / params.bus_to_process) and idempotent per (bu, report_date) (delete-then-insert), so replaying a historical window requires no change to core pipeline or Klair logic. The only deliverable in this PR is an additive, reviewable runner — src/backfill.py — that orchestrates the existing handler over month-by-month windows, plus a read-only probe and read-only verification SQL.
Linear: [SURTR-220](https://linear.app/builder-team/issue/SURTR-220)
## Why the gap exists
The daily cron pulls forward-only (each run fetches day-before-yesterday → yesterday), so core_finance.ai_spend_claude_token_usage has a hard floor at 2025-10-01. That floor is a go-live boundary that was never backfilled — not an Anthropic API retention limit. Meanwhile ~$174K of Q3'25 billed Anthropic spend already exists in the cost-reports table with zero corresponding token-usage rows, so the AI Spend page shows nothing for Jul–Sep 2025.
## Read-only probe results ✅
The orchestrator ran the read-only probe mode live against Anthropic's Usage Report API (zero DB writes, zero handler invocation). Anthropic still serves Q3'25 usage, confirming the backfill is feasible:
- probe --date 2025-09-15 (BU IgniteTech): YES — 32 usage items returned (standard tier; 0 fast).
Sample record: {report_date: 2025-09-15, model: claude-3-5-sonnet-20241022, uncached_input_tokens: 2372, output_tokens: 561, ...}
- probe --date 2025-07-15 (BU IgniteTech): YES — 19 usage items returned.
(Confirms both edges of the Q3 window are retrievable, not just the tail.)
- Secret Anthropic-Usage-Keys resolved 7 BUs.
- The probe made zero database calls.
Conclusion: the historical data is retrievable from Anthropic, so the Q3'25 backfill is feasible.
## What's in this PR
- pipelines/runners/claude-token-spend-pipeline/src/backfill.py — additive CLI runner with three modes:
- probe — read-only check that Anthropic returns Q3'25 data (no handler, no DB).
- backfill — chunked per-calendar-month replay of the existing handler.handler(...) path. Dry-run by default; real writes require an explicit --execute (alias --no-dry-run).
- verify — read-only validation SELECTs (bounds / monthly / Q3-presence / cost-reports cross-check); --sql-only prints SQL without an AWS session.
- 22 unit tests (tests/test_backfill.py).
- Spec 05 (05-q325-token-usage-backfill) and the FEATURE.md changelog update.
No new dependencies (stdlib + already-bundled boto3 / requests). AWS clients are imported lazily, so CI and the unit tests need no AWS session.
## Not in this PR (operator runs the actual backfill)
The production, DB-writing backfill is intentionally NOT executed by this PR. Scope here is *tooling + read-only probe only*. After review, the operator runs backfill --execute locally (authenticated via saml2aws). The dry-run default and the explicit --execute gate make the write path opt-in by construction.
## Operator runbook
Copy-pasteable sequence (run from the worktree / repo root unless noted):
1. Authenticate:
saml2aws login --profile default --force --username ashwanth.r \--role "arn:aws:iam::479395885256:role/RAM-AWS-Int-CentralFunctions-CentralFinance-Admin" \
--skip-prompt
2. (optional) re-probe Q3'25 availability:
cd pipelines/runners/claude-token-spend-pipeline && uv run python src/backfill.py probe
3. Dry-run preview (shows the month/BU plan, writes nothing):
uv run python src/backfill.py backfill
4. Execute — ideally one month at a time for safety:
uv run python src/backfill.py backfill --start-month 2025-07 --end-month 2025-07 --executeuv run python src/backfill.py backfill --start-month 2025-08 --end-month 2025-08 --execute
uv run python src/backfill.py backfill --start-month 2025-09 --end-month 2025-09 --execute
(or all three at once: --start-month 2025-07 --end-month 2025-09 --execute).
Run locally — a 3-month all-BU window exceeds the 600s Lambda timeout, which is why the runner chunks per month and is run from a workstation rather than the Lambda.
5. Verify (read-only — bounds / monthly / Q3-presence / cost-reports cross-check):
uv run python src/backfill.py verify
Re-runs are safe: writes are idempotent per (bu, report_date), and existing Oct'25+ rows are never touched by a Q3'25 replay.
6. Optional extension — close the full ~$277.5K pre-go-live gap (Dec'24 → Jun'25) with the same procedure:
uv run python src/backfill.py backfill --start-month 2024-12 --end-month 2025-06 --execute
## Test coverage
22 passing unit tests (uv run pytest tests/test_backfill.py -q) covering:
- Month-window math — [first-of-month, first-of-next-month) with exclusive ends, including year rollover (Dec → Jan).
- CLI parsing / defaults — Q3'25 defaults require no arguments; --start-month after --end-month raises ValueError.
- Dry-run safety — in dry-run the handler is never invoked and nothing is written.
- Verify SQL — all four queries are SELECT-only (no write path).
## Spec
[features/surtr/ai-spend-pipeline/specs/05-q325-token-usage-backfill/spec.md](features/surtr/ai-spend-pipeline/specs/05-q325-token-usage-backfill/spec.md)
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