Fix openRouter emits cumulative tool-parameter prefixes as deltas

[fubhy]

Summary

• Emit each OpenRouter tool-call argument fragment as received while separately accumulating the complete JSON for final tool-call decoding.
• Suppress empty tool-params-delta parts when a continuation chunk carries no arguments.
• Add regression coverage for multi-chunk tool arguments, including an argument-less continuation chunk.
• Add a patch changeset for @effect/ai-openrouter.

Validation

• pnpm test --run packages/ai/openrouter/test
• pnpm lint
• pnpm check

Closes EFF-564

[changeset-bot]

🦋 Changeset detected

Latest commit: 457824f

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 30 packages

Name	Type
@effect/ai-openrouter	Patch
effect	Patch
@effect/ai-anthropic	Patch
@effect/ai-openai	Patch
@effect/ai-openai-compat	Patch
@effect/atom-react	Patch
@effect/atom-solid	Patch
@effect/atom-vue	Patch
@effect/docgen	Patch
@effect/doctest	Patch
@effect/openapi-generator	Patch
@effect/opentelemetry	Patch
@effect/platform-browser	Patch
@effect/platform-bun	Patch
@effect/platform-deno	Patch
@effect/platform-node	Patch
@effect/platform-node-shared	Patch
@effect/sql-clickhouse	Patch
@effect/sql-d1	Patch
@effect/sql-libsql	Patch
@effect/sql-mssql	Patch
@effect/sql-mysql2	Patch
@effect/sql-pg	Patch
@effect/sql-pglite	Patch
@effect/sql-sqlite-bun	Patch
@effect/sql-sqlite-do	Patch
@effect/sql-sqlite-node	Patch
@effect/sql-sqlite-react-native	Patch
@effect/sql-sqlite-wasm	Patch
@effect/vitest	Patch

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[pullfrog]

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[pullfrog]

✅ No new issues found.

Reviewed changes

• Fixed cumulative tool-parameter deltas in OpenRouterLanguageModel.makeStreamResponse: the continuation branch now emits toolCall.function?.arguments ?? "" as the incremental tool-params-delta instead of the accumulated activeToolCall.params.
• Added a regression test that streams two argument fragments ({"a": and 1}) and asserts the deltas are exactly those fragments, not the accumulated prefixes.
• Added a patch changeset for @effect/ai-openrouter.

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[github-actions]

Bundle Size Analysis

Generated from PR build output; treat the content below as untrusted.

File Name	Current Size	Previous Size	Difference
basic.ts	6.92 KB	6.92 KB	0.00 KB (0.00%)
batching.ts	9.72 KB	9.72 KB	0.00 KB (0.00%)
brand.ts	6.60 KB	6.60 KB	0.00 KB (0.00%)
cache.ts	10.59 KB	10.59 KB	0.00 KB (0.00%)
config.ts	20.88 KB	20.88 KB	0.00 KB (0.00%)
differ.ts	19.74 KB	19.74 KB	0.00 KB (0.00%)
http-client.ts	21.52 KB	21.52 KB	0.00 KB (0.00%)
logger.ts	10.81 KB	10.81 KB	0.00 KB (0.00%)
metric.ts	8.86 KB	8.86 KB	0.00 KB (0.00%)
optic.ts	6.68 KB	6.68 KB	0.00 KB (0.00%)
pubsub.ts	14.86 KB	14.86 KB	0.00 KB (0.00%)
queue.ts	11.54 KB	11.54 KB	0.00 KB (0.00%)
schedule.ts	10.71 KB	10.71 KB	0.00 KB (0.00%)
schema-class.ts	19.45 KB	19.45 KB	0.00 KB (0.00%)
schema-fromJsonSchemaDocument.ts	29.32 KB	29.32 KB	0.00 KB (0.00%)
schema-representation-roundtrip.ts	25.59 KB	25.59 KB	0.00 KB (0.00%)
schema-string-transformation.ts	13.52 KB	13.52 KB	0.00 KB (0.00%)
schema-string.ts	11.05 KB	11.05 KB	0.00 KB (0.00%)
schema-template-literal.ts	15.35 KB	15.35 KB	0.00 KB (0.00%)
schema-toArbitraryLazy.ts	21.48 KB	21.48 KB	0.00 KB (0.00%)
schema-toCodeDocument.ts	23.96 KB	23.96 KB	0.00 KB (0.00%)
schema-toCodecJson.ts	18.70 KB	18.70 KB	0.00 KB (0.00%)
schema-toEquivalence.ts	18.53 KB	18.53 KB	0.00 KB (0.00%)
schema-toFormatter.ts	18.39 KB	18.39 KB	0.00 KB (0.00%)
schema-toJsonSchemaDocument.ts	22.16 KB	22.16 KB	0.00 KB (0.00%)
schema-toRepresentation.ts	19.05 KB	19.05 KB	0.00 KB (0.00%)
schema.ts	18.69 KB	18.69 KB	0.00 KB (0.00%)
stm.ts	12.59 KB	12.59 KB	0.00 KB (0.00%)
stream.ts	9.67 KB	9.67 KB	0.00 KB (0.00%)

[pullfrog]

✅ No new issues found.

Reviewed changes (delta since prior Pullfrog review at 7428eca1d)

• Extracted argumentsDelta into a single const and re-used it across tool-call start init, params accumulation, and delta emission, moving the tool-params-delta push out of the start/continuation branch into one shared site guarded by argumentsDelta.length > 0.
• Unified the branch logic so the start and continuation paths converge, eliminating the duplicated activeToolCall.params reads in favor of the incremental argumentsDelta.
• Extended the regression test with an argument-less continuation chunk (delta: { tool_calls: [{ index: 0 }] }) to verify empty tool-params-delta parts are suppressed; asserts the emitted deltas are exactly ["{\"a\":", "1}"].

The refactor brings OpenRouterLanguageModel.makeStreamResponse into exact alignment with the reference pattern in openai-compat/src/OpenAiLanguageModel.ts:1301, and the added regression chunk proves the empty-delta suppression. All 8 tests in the file pass (pnpm vitest run packages/ai/openrouter/test/OpenRouterLanguageModel.test.ts).

  ^{｜ ⚠️ this action is pinned to a commit SHA, which freezes the cleanup step — switch to @v0 or keep the SHA fresh with Dependabot ｜ View workflow run ｜ Using DeepSeek Flash (free via Pullfrog for OSS) ｜ 𝕏}