[ENHANCEMENT] Provider specific file reading limits

[ad-astra-video]

Problem (one or two sentences)

I would like to limit file reads on slower local providers (e.g. Kimi K2.5 on old Xeon server) that have slower prompt processing. This would let more requests complete successfully rather than timeout.

Reading 2000 lines works on my fully GPU local providers but fails a lot on my slow mostly CPU provider.

Context (who is affected and when)

Users with providers that are fast, either GPU fully or cloud based, and some slower local providers on prompt processing.

Desired behavior (conceptual, not technical)

File reads are limited to provider line count override

Constraints / preferences (optional)

No response

Request checklist

• I've searched existing Issues and Discussions for duplicates
• This describes a specific problem with clear context and impact

Roo Code Task Links (optional)

No response

Acceptance criteria (optional)

A provider override for file read limit

Proposed approach (optional)

No response

Trade-offs / risks (optional)

No response

[roomote]

I've analyzed this issue and here's my proposed implementation plan:

Problem

The read_file tool defaults to a 2000-line limit (defined as DEFAULT_LINE_LIMIT in src/core/prompts/tools/native-tools/read_file.ts). This works well for fast GPU/cloud providers but causes timeouts on slower local CPU-based providers. There is currently no way to configure this limit per-provider.

Proposed Approach

1. Add maxReadFileLineLimit to provider settings schema

• Add an optional maxReadFileLineLimit: z.number().int().min(1).optional() field to baseProviderSettingsSchema in packages/types/src/provider-settings.ts
• This makes it available across all provider types since they all extend the base schema

2. Thread the setting through to the tool definition

• Update ReadFileToolOptions in src/core/prompts/tools/native-tools/read_file.ts to accept a maxLineLimit option
• Update createReadFileTool() to use the override in the tool description (so the model is told about the lower limit)
• Pass the setting from buildNativeToolsArray() in src/core/task/build-tools.ts which already has access to apiConfiguration

3. Enforce the limit at execution time

• In ReadFileTool.processTextFile() (src/core/tools/ReadFileTool.ts), clamp the effective limit to Math.min(requestedLimit, providerMaxLimit) so the provider's configured limit is always respected, even if the model requests more
• Get the provider setting via task.providerRef which is already available in the tool execution context

4. Apply to @ mention file reads

• The mention system in src/core/mentions/index.ts also uses DEFAULT_LINE_LIMIT -- apply the same override there for consistency

5. Add UI setting

• Add a "Max File Read Lines" numeric input to the provider settings UI, alongside existing settings like modelMaxTokens and rateLimitSeconds

This approach ensures:

• The model is told about the lower limit in the tool description (preventing it from requesting large reads)
• The limit is enforced server-side even if the model ignores the description
• The setting is per-provider profile, so users can have different limits for different providers
• Both tool calls and @ mention reads respect the setting

Please mention @roomote in a comment saying that you approve this plan, and I'll proceed with the implementation.

[ad-astra-video]

@roomote the plan seems ok to me. Should probably involve a core contributor before executing though :).

[roomote]

Thanks @ad-astra-video for the feedback! I've seen your comment and will proceed with implementing the plan. I'll open a draft PR to share progress -- feedback and guidance from core contributors are welcome.

[roomote]

Opened a draft PR with my attempt at implementing this: #11408

Adds a per-provider maxReadFileLine setting in Advanced Settings that overrides the default 2000-line limit for both tool calls and @ mention reads. The model is told about the lower limit in the tool description, and the limit is enforced server-side even if the model ignores it.

Feedback welcome!