[BUG] Could you configuration the file-reading line limit again?

[a1403951401]

Problem (one or two sentences)

When the model works with i18n translation files or other relatively large files, it often fails to read them. We end up editing with PowerShell or bash, then trying again and using Python to apply the changes.

Context (who is affected and when)

Reproduction steps

Model: MiniMax 2.5 (and actually not just this model)

Expected result

Configure the maximum number of lines to read from a file.

Actual result

Repeatedly attempt to read the file.

Variations tried (optional)

No response

App Version

Version: 3.50.5 (961d340)

API Provider (optional)

None

Model Used (optional)

No response

Roo Code Task Links (optional)

No response

Relevant logs or errors (optional)

[a1403951401]

One of the worktrees even spent the entire afternoon repeatedly trying different ways to read the file while checking the code logic, which ended up exhausting 5 hours of quota across 8 Codex accounts.

Model: gpt-5.3-codex

[roomote-v0]

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

Summary

The maxReadFileLine setting was partially scaffolded (it exists in the ExtensionState type and the webview context default values) but was never fully wired up. It is not persisted, not exposed in the settings UI, and not used by the actual ReadFileTool. This plan completes that wiring so users can configure the maximum number of lines the read_file tool returns.

Changes

1. Add maxReadFileLine to globalSettingsSchema (packages/types/src/global-settings.ts)

   • Add maxReadFileLine: z.number().optional() to the schema so the setting is persisted via VS Code global state.

2. Wire maxReadFileLine through ClineProvider.getState() (src/core/webview/ClineProvider.ts)

   • Read the persisted value and include it in the state object sent to the webview, following the same pattern as maxImageFileSize.

3. Add a UI control in ContextManagementSettings.tsx (webview-ui/src/components/settings/ContextManagementSettings.tsx)

   • Add a numeric input for "Max Read File Lines" in the Context Management settings section, following the same pattern as the existing maxImageFileSize control.
   • Default value: -1 (meaning use the built-in default of 2000 lines). Valid range: -1 to 100000 (where -1 means "use default").

4. Wire maxReadFileLine into SettingsView.tsx save logic

   • Include maxReadFileLine in the settings payload sent on save, similar to how maxImageFileSize is handled.

5. Pass maxReadFileLine through build-tools.ts to createReadFileTool() (src/core/task/build-tools.ts and src/core/prompts/tools/native-tools/read_file.ts)

   • Add maxReadFileLine to ReadFileToolOptions so the tool description dynamically reflects the configured limit (e.g., "returns up to N lines" instead of always saying 2000).

6. Use the configured limit in ReadFileTool.ts (src/core/tools/ReadFileTool.ts)

   • When computing the effective line limit, use the user's configured maxReadFileLine (if set and > 0) instead of the hardcoded DEFAULT_LINE_LIMIT. This affects both slice mode and the legacy code path.

7. Add i18n strings for the new setting label and description in the English locale file.

8. Update tests for the affected components (ReadFileTool, SettingsView, ContextManagementSettings, build-tools).

How It Works

• When maxReadFileLine is -1 (default) or not set, the behavior is identical to today (2000 line limit).
• When set to a positive number, that number becomes the effective line limit for the read_file tool.
• The tool's description in the system prompt dynamically reflects the configured limit.
• The limit parameter in read_file still works as before -- it caps at the configured maximum.

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