fix(usage): tolerate newer provider variants

[tris203]

What Changed

Use the existing ForwardCompatibleArray codec for usage buckets and sources. Clients skip entries they cannot decode and retain known usage, while the server continues encoding the complete response. Add focused decode/merge regression tests and a short user-guide note about provider coverage.

Why

An unfamiliar provider or pricing variant currently rejects the entire usage summary, so a client can show “could not report usage” even when the server successfully scanned its transcripts. This follows the existing server-provider list compatibility pattern and keeps the incompatible contract-version guard. Additive provider variants should not bump the contract version.

This is a client decoder fix and requires an updated client; it does not repair already-installed Android 1.0.3 clients through a server update alone.

Validation

• 16 usage merge tests passed, covering unfamiliar entries, retained totals, complete encoding, malformed envelopes, and incompatible versions.
• Scoped contracts/shared typechecks and targeted lint passed.

Checklist

• This PR is small and focused
• I explained what changed and why

Model: GPT-6. Harness: Codex.

Note

Tolerate unknown provider variants in UsageSummary decoding

• Replaces strict array schemas for usage buckets and sources in usage.ts with a forward-compatible schema that skips unknown array entries while still validating the surrounding summary structure
• Model names are now normalized during decoding, so variants differing only by whitespace group into one model result during merging
• Adds tests covering unknown provider buckets/sources, model-name normalization, round-trip encoding for supported providers, malformed-envelope rejection, and newer contract-version exclusion
• Updates usage.md to note that totals only cover providers the app understands and that the app must be updated for new providers
• Risk: UsageSummary decoding silently drops unknown bucket/source entries; callers that relied on strict rejection of unexpected providers will no longer see errors for those entries

^{Macroscope summarized 195f446.}

Summary by CodeRabbit

• New Features
  • Usage summaries can be processed across app and server versions with differing provider support. Recognized usage entries remain available when responses contain unfamiliar providers or usage categories; unsupported entries may be excluded.
• Documentation
  • Added guidance that usage totals may cover only providers recognized by the app, and updating the app enables support for newly added providers.

[macroscopeapp]

Approvability

Verdict: Approved at 195f446

Macroscope's review found this PR approvable — This is a small, well-tested usage compatibility fix that preserves known totals when newer provider variants appear, while retaining strict validation of the response envelope and contract version. Documentation and tests account for the partial-coverage behavior, with no broader production or infrastructure changes.

Notes:

• No code objects were reviewed. Approvability was decided on eligibility alone.

No code changes detected at 6c6fe72. Prior analysis still applies.

^{You can add or adjust custom eligibility rules. Learn more.}

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📝 Walkthrough

Walkthrough

Usage summary bucket and source arrays now use forward-compatible decoding. Tests cover unknown variants, model-name normalization, round trips, malformed summaries, and newer contract versions. User documentation describes provider differences between app and server versions.

Changes

Usage compatibility

Layer / File(s)	Summary
Usage contract decoding packages/contracts/src/usage.ts, docs/user/usage.md	UsageSummary.buckets and UsageSummary.sources use ForwardCompatibleArray. Contract comments describe array-element variants as additive. The documentation notes that usage totals may include only providers the app understands.
Usage summary validation packages/shared/src/usageMerge.test.ts	Tests cover unknown providers and bucket variants, model-name normalization, supported-provider round trips, malformed summaries, and newer contract versions.

Priority: ⬇️ Low

Estimated code review effort: 2 (Simple) | ~10 minutes

Change: Bug fix

Suggested reviewers: maria-rcks, juliusmarminge

Merge Risk: 🟡 Moderate · up to 6c6fe

Malformed usage from a supported provider can appear as a lower total without an error. Distinguish malformed known entries from unsupported variants before merging.

Security Architecture Review

Security architecture risk: 🔵 Low · up to 6c6fe

Updated clients can show known usage when a server reports unfamiliar variants, but the displayed total may omit unsupported usage. The change does not appear to add an access path or weaken the contract-version guard.

Retained concerns
No architecture-level concerns identified.

Security review details

Security Blast Radius

• inferred — The newly accepted data affects usage displayed from existing connected-environment summaries. The examined contract and merge path show no new route, privilege, or downstream sink.

Trust Boundaries and Controls

• observed — Response decoding can discard unknown array elements, but it still applies the known element schemas; the separate merge-time contract-version check remains in place.

🚥 Pre-merge checks | ✅ 4 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 0.00% which is insufficient. The required threshold is 80.00%. Docstring coverage is scoped to functions touched by this diff. Analyzed 1 functions across 2 files. (1 skipped: 1 …	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (4 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title clearly and concisely describes the main change: making usage decoding tolerate newer provider variants.
Description check	✅ Passed	The description explains what changed, why it changed, validation performed, and the client-update limitation. It is focused and substantially matches the required template. The omitted UI Changes sec…
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

Full details: Docstring Coverage

Explanation

Docstring coverage is 0.00% which is insufficient. The required threshold is 80.00%. Docstring coverage is scoped to functions touched by this diff. Analyzed 1 functions across 2 files. (1 skipped: 1 unsupported.)

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✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create a new PR

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Actionable comments posted: 1

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🤖 Prompt to fix review comments

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only still-valid issues, skip the rest with a brief reason, keep changes
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Inline comments:
In `@packages/contracts/src/usage.ts`:
- Around line 206-207: Update the `buckets` and `sources` decoders using
`UsageBucket` and `UsageSource` so malformed entries for recognized variants
fail decoding, while unsupported variants continue to be skipped. Distinguish
unsupported variants from invalid known variants before filtering, rather than
letting `ForwardCompatibleArray` discard both.

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ℹ️ Review info

⚙️ Run configuration

Configuration used: Repository: pingdotgg/t3code/.coderabbit.yaml

Review profile: CHILL

Plan: Advanced

Run ID: 93951001-4969-4b5b-b64f-57c5ae411065

📥 Commits

Reviewing files that changed from the base of the PR and between a60d655 and 6c6fe72.

📒 Files selected for processing (3)

• docs/user/usage.md
• packages/contracts/src/usage.ts
• packages/shared/src/usageMerge.test.ts

🚧 Files skipped from review as they are similar to previous changes (1)

• docs/user/usage.md

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