fix(usage): count each Antigravity call once

[leorivastech]

What Changed

• metadata() treats the per-attempt list (steps field 28, generations field 1 → 17) as the attempts of a call: when the main usage is the field-by-field sum of the attempts, and no attempt carries a different response id, the main usage is a total. With a single attempt the two are the same usage and the main copy is kept, response ids included; with a retried call the attempts become the records and the total is not added on top, unless the attempts share a response id, in which case the total stays as one record so the id merge cannot collapse them.
• usageCandidates() gives id-less step and generation usages with identical counters a shared key, nth with nth, scoped to the database they came from. The existing merge then folds the two copies into one record, keeping the earliest timestamp and the step's model label, exactly as it already does for copies that share a response id.
• Five tests: id-less step + generation + list copy (3 records on main, 1 here); a retried call stored as a total with two attempts and two steps (5 on main, 2 here); a list entry with another response id stays apart; a single attempt without an id keeps the main copy and its response id; attempts that share one response id keep the total as one record. The existing retry-1 fixture is unchanged.

Why

Fixes #17071.

Antigravity writes the usage of one model call to up to three places of a conversation database. The reader turned every copy into a record and only merged the ones that carried a response id. Conversations written by the ACP provider carry no ids, so every call was counted three times. The step copy and the generation copy also name the model differently (gemini-3.8-flash-high on the step, gemini-3.8-flash-n on the generation), so the same call showed up under two model rows.

I use Antigravity both as a T3 provider and through its own CLI on this machine, so the bug is confirmed on real data, not only on the made-up database from the triage. On the 76 conversations here (20 from the Antigravity CLI, 56 from T3's Antigravity profile), id-less copies produced 7,769 records for 2,591 calls and 788 M tokens instead of 263 M; the app's conversations carry ids and were already right. Pairing by counters reproduced the id-based pairing in every one of the 132 id-bearing pairs, and no conversation had two different calls with identical counters. steps.idx and gen_metadata.idx never coincide for the same call, so pairing by index is not an option.

The triage's rule (drop a list entry equal to the main usage) is what this does for single attempts. One retried call in the data showed why the list is treated as attempts instead: the generation held the total with two entries that summed to it, and the two attempts were stored as two separate steps. With the triage's rule that call stayed counted twice.

Not changed here: generationModels.get(idx) still assumes step and generation indexes line up when a step has no model name, so a few step-only calls get another call's label. That is a separate, pre-existing label issue.

Testing

• vp test apps/server/src/provider/Drivers/antigravityUsageReader.test.ts --run (the five new tests; three of them fail on main and all pass here)
• vp test apps/server/src/usage apps/server/src/provider/Drivers --run (229/229)
• tsc --noEmit -p apps/server/tsconfig.json, vp lint and vp fmt --check on the changed files
• The reader run on the real databases before and after, with the script from the issue: Antigravity CLI 154 → 154 calls (they carry ids and were already merged); T3 profile 7,769 records → 2,609, which equals the number of non-empty step usages; the one retried call in the data goes from 3 records to 2.
• After merging main at 5ce5a8f (the reader moved to provider/Drivers in refactor(usage): Antigravity usage is a reader on its driver #17579 and refactor(usage): usage readers use Effect FileSystem and SqlClient #17615), the same comparison on today's databases, 123 from the Antigravity CLI and 107 from T3's profile: CLI 589 → 589 records; T3 profile 14,361 records and 1,495 M tokens → 4,790 records and 499 M tokens, which equals the number and the token total of the non-empty step usages counted with a separate script.
• Three fresh Antigravity conversations made for this check, with a known number of model calls (1, 2 and 6, counted as tool actions plus the final answer): main reported 3, 6 and 18 records; this branch reports 1, 2 and 6, with the same token totals as the step usages.
• Pairing by counters was checked against the id-based pairing on the 132 id-bearing pairs: identical. No conversation had two different calls with identical counters. Step and generation timestamps of one call are under 100 s apart, so merging never moves a call to another day.

Checklist

• This PR is small and focused
• I explained what changed and why
• No UI changes, so no screenshots or video

Model and harness: analysis and review with Claude Fable 5.1 and Claude Opus 5.5 in Claude Code inside T3 Code; implementation and tests with Codex GPT-6.1, and independent checks of the data with Gemini 3.1 Pro (Antigravity) and Grok 4.7 (Cursor), all as T3 Code subagents. The port onto the relocated reader was done with Claude Opus 5.5 in Claude Code inside T3 Code.

[macroscopeapp]

Approvability

Verdict: Not approved

Macroscope's review found this PR not approvable — This focused fix changes production Antigravity usage records, including the token and cost totals produced by downstream aggregation. Because it affects metering results, human review is warranted despite the localized implementation and extensive regression coverage.

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• apps/server/src/provider/Drivers/antigravityUsageReader.test.ts
• apps/server/src/provider/Drivers/antigravityUsageReader.ts

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📝 Walkthrough

📝 Walkthrough

Walkthrough

The Antigravity usage reader now distinguishes generation totals from retry attempts and assigns matching keys to id-less usage copies within a database. Added tests cover retry aggregation, response-ID handling, and deduplication of step, generation, and list records.

Changes

Antigravity usage records

Layer / File(s)	Summary
Retry metadata parsing apps/server/src/provider/Drivers/antigravityUsageReader.ts, apps/server/src/provider/Drivers/antigravityUsageReader.test.ts	The reader returns individual attempts when main counters match their total and the attempts have distinct response IDs. It returns the main record in other matching-total cases, and retains both main and retry records when their counters do not match. Tests cover these cases and distinct response IDs in list entries.
ID-less usage keys apps/server/src/provider/Drivers/antigravityUsageReader.ts, apps/server/src/provider/Drivers/antigravityUsageReader.test.ts	usageCandidates now receives the database path and uses it with serialized counters and an occurrence number to key usages without response IDs. A test checks that matching step, generation, and list copies produce one record.

Priority: ➖ Normal

Estimated code review effort: 3 (Moderate) | ~20 minutes

Change: Bug fix · Severity of issue fixed: Low

Suggested reviewers: juliusmarminge

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Merge Risk: ⚪ Minimal · up to a9f0c

This change makes Antigravity usage count each model call once instead of inflating requests and tokens. No concrete merge-blocking problem was identified, and the PR includes tests for the retry and deduplication cases.

Security Architecture Review

Security architecture risk: ⚪ Minimal · up to a9f0c

The change corrects duplicate usage counting within existing data sources. No new permissions, access paths, or security-sensitive behavior were found in the reviewed flow.

Retained concerns
No architecture-level concerns identified.

Security review details

Security Blast Radius

• inferred — A party able to modify a scanned conversation database can influence reported usage and attribution. New ID-less matching is bounded to that database path; existing response-ID matching can still span configured stores. The inspected downstream flow performs usage deduplication, bucketing, and cost estimation, not privilege or tenant selection.

Trust Boundaries and Controls

• observed — Database metadata remains input to the same local reporting pipeline. Reads use fixed SQL statements, decoding failures become per-file errors, and the provider reports affected roots as partial. Retry reconciliation does not introduce a new credential, permission, or execution sink.

Resilience and Maintainability Implications

• observed — Database reads occur within a transaction. Cache entries are replaced only after successful decoding; fingerprints include the database and WAL metadata. Merge state is invocation-local, failed files are omitted and reported, and completed scans prune unvisited cache entries. These existing mechanisms contain partial reads without publishing partially assembled cached candidates.

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Pre-merge checks | 4

✅ Passed checks (4 passed)

Check name	Status	Explanation
Linked Issues check		The PR meets the coding requirements in [#17071]. metadata() handles totals and retry attempts without double counting. usageCandidates() pairs id-less step and generation usages by counters and o…
Out of Scope Changes check		The changes are limited to the Antigravity usage reader and focused reader tests. The changes directly support [#17071]. The separate model-label issue remains excluded as stated in the PR description…
Title check		The title clearly and concisely describes the primary change: counting each Antigravity usage call once.
Description check		The description clearly explains the problem, implementation, linked issue, verification steps, observed results, scope, and out-of-scope behavior. It is mostly complete despite using headings that di…

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Actionable comments posted: 1

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🤖 Prompt to fix review comments

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Inline comments:
Review comments at @apps/server/src/usage/antigravityUsageReader.ts:
- Line 157: Update the usage selection and response-ID merge around
`mainIsTotal` so `main`’s aggregate counters are not discarded when attempts
share its nonempty merge key and are combined using per-counter maximums.
Preserve the summed aggregate in the merged result, and add a test covering two
attempts with the same ID and input token counts of 100 and 200.

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