fix(claude): strip empty Read pages tool input

[makcimbx]

Summary

• Adds a Claude Code Read tool-call shim that removes invalid empty pages placeholders before streaming tool input back to Claude Code.
• Preserves valid non-empty PDF page ranges.
• Extends Responses → Chat tool argument cleanup to handle JSON-string item.arguments, not only object arguments.
• Adds unit coverage for helper-level cleanup, streaming input_json_delta behavior, and JSON-string Responses arguments.

Closes #2935
Addresses #2889

Test Plan

npm exec -- cross-env DISABLE_SQLITE_AUTO_BACKUP=true node --max-old-space-size=4096 --import tsx --import ./open-sse/utils/setupPolyfill.ts --test --test-force-exit tests/unit/translator-tool-call-shim.test.ts tests/unit/translator-resp-openai-responses.test.ts

Result: 32 passing, 0 failing.

[gemini-code-assist]

Code Review

This pull request introduces a Read tool shim to filter out empty pages arguments from non-Anthropic models and refactors the argument cleaning logic in openai-responses.ts into a reusable stripEmptyOptionalToolArgs helper, supported by new unit tests. Feedback on these changes highlights a potential bug in stripEmptyOptionalToolArgs where using the logical OR operator (||) for a fallback value could inadvertently replace valid falsy JSON values (such as false or 0) with {}. It is recommended to use the nullish coalescing operator (??) instead to preserve these values.

[gemini-code-assist]

Using the logical OR operator (||) to provide a fallback value of {} will cause any valid falsy JSON values (such as false, 0, or "") to be incorrectly replaced with {}. For example, if a tool argument is a stringified boolean "false", it will be parsed as false, cleaned as false, and then false || {} will evaluate to {}, resulting in "{}" being returned instead of "false".

Using the nullish coalescing operator (??) instead ensures that only null or undefined values are coalesced to {}, preserving other valid falsy values.

Suggested change

	if (typeof value === "string") {
	try {
	const parsed = JSON.parse(value);
	const cleaned = stripEmptyOptionalToolArgs(parsed);
	return JSON.stringify(cleaned || {});
	} catch {
	return value;
	}
	}
	if (typeof value === "string") {
	try {
	const parsed = JSON.parse(value);
	const cleaned = stripEmptyOptionalToolArgs(parsed);
	return JSON.stringify(cleaned ?? {});
	} catch {
	return value;
	}
	}

[makcimbx]

Follow-up after the bot review: addressed in later commits.

• 3767e13 replaced the cleaned || {} fallback with cleaned ?? {} so valid falsy JSON values are preserved.
• d25e323 further narrowed JSON-string argument cleanup to the Claude Code Read tool only. Non-Read JSON-string tool arguments are now preserved as-is, because empty strings/arrays can be valid payloads for arbitrary tools.
• Added regression coverage for falsy JSON-string arguments, non-Read JSON-string arguments, non-object Read JSON strings, and the original Read.pages cleanup path.

Local verification after the follow-up changes:

tests/unit/translator-tool-call-shim.test.ts
tests/unit/translator-resp-openai-responses.test.ts
35 passing, 0 failing

[diegosouzapw]

Thank you for your contribution! This PR has been reviewed and integrated into the upcoming v3.8.8 release. 🎉