Agent Mode: add copy buttons to chat log

[marksftw]

Summary

• add copy actions below Agent Mode user prompts and assistant responses
• extract the existing standard-chat copy control into one shared ChatCopyButton
• copy raw message text while excluding thinking, tool activity, permission prompts, system events, and errors
• centralize user-action visibility in the shared chat-turn layout

Why

Agent Mode already reused the standard chat turn layout, but it did not wire actions into those shared turn shells. The existing clipboard control was private to UnifiedChat, so Agent Mode could not reuse it without first extracting the component.

Validation

• bun test — 93 passed
• bun run lint — 0 errors (12 pre-existing warnings)
• bun run build
• bun run format

Closes #629

Summary by CodeRabbit

• New Features

  • Added a shared message copy button across standard and unified chat views.
  • Enabled per-turn copy controls in agent timelines, with assistant turn text derived from the relevant assistant message.
  • Copy actions are suppressed for the currently active final assistant turn.

• Bug Fixes

  • Improved copy-control behavior and visibility consistency across different layouts.

• Tests

  • Expanded coverage for agent timeline copy-text generation and user-message “locked” detection.

[coderabbitai]

📝 Walkthrough

Walkthrough

Adds a shared ChatCopyButton, integrates copy actions into Unified Chat and Agent Mode turns, extracts copyable Agent timeline text, and updates ChatUserTurn styling and timeline tests.

Changes

Chat copy controls

Layer / File(s)	Summary
Copy contract and shared button frontend/src/components/chat/ChatCopyButton.tsx, frontend/src/components/chat/ChatTurn.tsx	Adds clipboard copying with transient success feedback and updates ChatUserTurn action styling and props.
Agent turn copy text frontend/src/services/agentTimeline.ts, frontend/src/services/agentTimeline.test.ts	Extracts user text and the latest assistant message text, with tests covering filtering and turn detection.
Chat rendering integration frontend/src/components/AgentMode.tsx, frontend/src/components/UnifiedChat.tsx	Renders the shared copy control for Agent Mode and standard chat turns, removing the local copy implementation.

Estimated code review effort: 3 (Moderate) | ~20 minutes

Sequence Diagram(s)

sequenceDiagram
  participant AgentTimeline
  participant AgentMode
  participant ChatCopyButton
  participant Clipboard
  AgentTimeline->>AgentMode: derive copy text for grouped turn
  AgentMode->>ChatCopyButton: render copy action
  ChatCopyButton->>Clipboard: write turn text
  Clipboard-->>ChatCopyButton: report copy result

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Possibly related PRs

• OpenSecretCloud/Maple#614 — Overlaps the Agent Mode timeline and shared turn rendering integration.
• OpenSecretCloud/Maple#622 — Also modifies nearby AgentMode.tsx logic.

Suggested reviewers: anthonyronning

Poem

I’m a bunny with buttons, a copy-ready trail,
User words and answers hop into the mail.
Click once—little check marks gleam,
Agent turns now share the same beam.

🚥 Pre-merge checks | ✅ 4

✅ Passed checks (4 passed)

Check name	Status	Explanation
Linked Issues check	✅ Passed	The PR adds copy buttons for user and assistant turns in Agent Mode and copies the intended message text, matching issue #629.
Out of Scope Changes check	✅ Passed	The changes stay focused on shared copy controls, copy-text extraction, and related tests, with no clear unrelated additions.
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title accurately summarizes the main change: adding copy buttons to the Agent Mode chat log.

✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch codex/agent-chat-copy-buttons

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_{Comment @coderabbitai help to get the list of available commands.}

[cloudflare-workers-and-pages]

Deploying maple with    Cloudflare Pages

Latest commit:	295602b
Status:	✅  Deploy successful!
Preview URL:	https://3ed15003.maple-ca8.pages.dev
Branch Preview URL:	https://codex-agent-chat-copy-button.maple-ca8.pages.dev

View logs

[devin-ai-integration]

✅ Devin Review: No Issues Found

Devin Review analyzed this PR and found no bugs or issues to report.

[AnthonyRonning]

Agent Mode should copy only the final assistant content message in a turn, rather than concatenating every assistant message around tool calls.

For a turn like:

assistant preamble → tool → tool result → assistant update → tool → tool result → final assistant

please have the copy action copy only the final assistant message. The earlier assistant messages, thinking, tools, tool results, permissions, system events, and errors should not be included.

Please also suppress the copy action on the currently active assistant turn until the run finishes, since otherwise an intermediate assistant message temporarily becomes copyable. Copy actions on earlier completed turns should remain available.

A focused test should cover assistant preamble → tool/result → final assistant and assert that only the final assistant text is copied.

[marksftw]

Addressed in 295602b.

• Agent Mode now copies only the final assistant content message in each turn; preambles, intermediate assistant updates, thinking, tools/results, permissions, system events, and errors are excluded.
• The copy action is suppressed on the currently active assistant turn until the run finishes, while earlier completed turns remain copyable.
• The focused timeline test now covers assistant preamble → tool/result → final assistant and asserts that only the final text is selected.

Validation: 93 tests pass, production build passes, and lint completes with 0 errors (12 existing warnings).

[AnthonyRonning]

Reviewed the updated implementation at 295602b. The final-message-only copy behavior and active-turn suppression match the requested Agent Mode behavior, with focused test coverage. Local validation passed; approving pending completion of the remaining required CI builds.