fix(copilot): keep a file-preview failure from stripping a tool call's arguments

[waleedlatif1]

Summary

• The workspace file preview adapter runs while the workspace_file tool-call frame is still on the wire, before per-call dispatch builds a call-scoped context — so the execution context it receives is turn-scoped and carries no toolCallId. The file delegation requires one, so resolving a path-shaped preview target threw on every call.
• The SSE handler swallows a handler throw and moves to the next event, which abandoned the rest of that event. The tool-call frame therefore never registered its arguments, and the call was later dispatched from the checkpoint with an empty payload — failing schema validation with every required property missing. The model got back an opaque error and retried the same call over and over, so the requested file edit never happened.
• Fix: bind the frame's own tool call id before entering the file use cases; resolve the preview target best effort (matching how the preview base load already degrades); and stop a preview failure from dropping a tool-call frame in the stream loop.
• The stream fixtures put a synthetic toolCallId on a turn-scoped context, a shape the chat lifecycle never produces — that is why the tests stayed green. Removed, so they now exercise the real shape.

Known-remaining, deliberately out of scope: prePersistClientExecutableToolCall sits in the same window before the frame registers its arguments and is likewise unguarded. It must not get the same swallow — it is where a gated call is stamped awaiting_approval, so swallowing there would let a gated tool through ungated. The structural answer is to register frame state before the presentation and persistence stages, which reorders emissions the client depends on.

Type of Change

• Bug fix

Testing

bun run type-check and bunx vitest run lib/copilot/request/go/ in apps/sim (27 passing). Reverting only the two source files turns 4 of them red, including the exact error string seen in production.

Checklist

• Code follows project style guidelines
• Self-reviewed my changes
• Tests added/updated and passing
• No new warnings introduced
• I confirm that I have read and agree to the terms outlined in the Contributor License Agreement (CLA)

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1 Skipped Deployment

Project	Deployment	Actions	Updated (UTC)
docs	Skipped		Aug 12, 2026 12:36pm

[cursor]

PR Summary

Medium Risk
Touches the copilot SSE stream loop and tool-call registration path, so a mistaken swallow could hide real failures—but the change is narrowly scoped to presentation-only preview handling.

Overview
Prevents a file-preview adapter failure from dropping workspace_file tool-call arguments during streaming.

The adapter now binds the frame's toolCallId onto the turn-scoped execution context before resolving path targets or loading preview bases, and treats path resolution as best-effort (log + keep the path target on failure). The stream loop also isolates preview processing in a try/catch so a presentation error no longer abandons the rest of the event and later dispatches the call with an empty payload.

Tests now use the real turn-scoped context shape (no synthetic toolCallId) and cover successful binding plus non-throwing resolution failure.

^{Reviewed by Cursor Bugbot for commit b7a3e4d. Configure here.}

[greptile-apps]

Greptile Summary

This PR prevents workspace-file preview failures from discarding the underlying streamed tool-call frame.

• Binds preview file operations to the tool-call ID carried by the current frame.
• Makes path-to-file preview resolution best effort.
• Isolates preview-adapter errors so normal tool-call registration and dispatch continue.
• Updates stream fixtures and adds regression coverage for turn-scoped execution contexts.

Confidence Score: 5/5

The PR appears safe to merge, with no concrete blocking or independently actionable non-blocking issues identified.

The changed error boundaries preserve the original tool-call frame after presentation failures, while call identity is supplied only to preview-related file operations and regression tests cover the production context shape.

Important Files Changed

Filename	Overview
apps/sim/lib/copilot/request/go/file-preview-adapter.ts	Binds streamed call identity to preview file operations and degrades target resolution without aborting the tool frame.
apps/sim/lib/copilot/request/go/stream.ts	Contains preview-processing failures while preserving subsequent persistence, event forwarding, and dispatch.
apps/sim/lib/copilot/request/go/file-preview-adapter.test.ts	Adds coverage for call-scoped identity binding and failed path resolution.
apps/sim/lib/copilot/request/go/stream.test.ts	Aligns stream fixtures with the lifecycle's turn-scoped execution-context shape.

Sequence Diagram

sequenceDiagram
  participant M as Mothership
  participant S as Stream loop
  participant P as File preview adapter
  participant F as File use case
  participant H as Tool event handler
  M->>S: workspace_file call frame
  S->>P: Process preview with turn context
  P->>P: Bind frame toolCallId
  P->>F: Resolve preview target
  alt Resolution succeeds
    F-->>P: Matching workspace file
    P-->>S: Resolved preview target
  else Resolution or preview fails
    F--xP: Error
    P-->>S: Preserve path target or throw
    S->>S: Log preview failure
  end
  S->>H: Persist and register original frame
  H-->>S: Arguments retained for dispatch

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