feat(attach): warn on empty transcript, capture footer, amend-fail note

[computermode]

https://entire.io/gh/entireio/cli/trails/699

What

Improves entire attach diagnosability and feedback across four small, related changes — no behavioral regressions, attach still always writes the checkpoint.

1. Warn on a transcript that parses to nothing (highest value). When extractTranscriptMetadata yields no first prompt and zero turns, attach previously produced a contentless checkpoint silently. It now emits a warning to stderr and continues. It stays a warning, not a hard error: agents whose user-content shape isn't matched by the generic JSONL/Gemini parser (codex/copilot/pi/factory) can legitimately yield empty metadata from a valid transcript, and token usage is still computed agent-specifically. Under --review the warning additionally calls out that the review prompt will be empty.

2. Post-attach summary footer. A real attach now prints Captured: <turns> · <model> · <tokens> from data already in scope, reusing the existing totalTokens/formatTokenCount helpers. Each segment is omitted when its value is absent (turns 0, empty model, nil token usage).

3. Surface the amend-failure reason. When --amend fails, the reason is now printed to stderr (Could not amend the commit automatically (...)) in addition to the existing debug log, so the user knows the best-effort amend was attempted before the manual-paste trailer fallback. Polish, not a correctness fix — the recovery path already worked.

4. Help-text accuracy. --force help notes the amend is best-effort; Long help documents transcript-based agent auto-detection.

How

• Threads an errW io.Writer through runAttach (the cobra caller passes cmd.ErrOrStderr()) so warnings/notes land on stderr, never interleaved with stdout success lines.
• Extracts three small helpers — warnEmptyTranscriptMetadata, printAttachFooter/attachSummaryLine, and amendOrPrintTrailer (the last de-duplicates the two amend call sites and keeps runAttach under the maintidx linter threshold).

Tests

Added TestAttach_WarnsOnEmptyTranscriptMetadata (+ _Review variant), TestAttachSummaryLine (footer builder incl. nil-token and empty cases), and TestAttach_NonInteractivePrintsTrailerForManualPaste. Existing runAttach call sites updated for the new signature.

Verification

mise run check passed: lint 0 issues, unit + integration (59 vogon) + e2e canary (4) all green.

Reviewer notes

• The amend hard-fail path isn't cleanly stubbable without injecting the git command, so it remains untested; the non-interactive trailer branch is covered instead.
• The empty-transcript warning reports the --agent flag value verbatim (per spec), which may be the claude-code default even when auto-detection later resolves a different agent.

---

Note

Low Risk
CLI-only UX and messaging around attach; checkpoint write semantics are unchanged and failures remain non-fatal where documented.

Overview
entire attach gets clearer CLI feedback without changing the core rule that a checkpoint is still written.

When transcript parsing yields no user prompts and zero turns, attach now warns on stderr (and continues). With --review, the warning also notes an empty review prompt. A new stdout line Captured: <turns> · <model> · <tokens> summarizes what was stored; segments are omitted when unknown.

Commit amend behavior is centralized in amendOrPrintTrailer: failures log and print Could not amend the commit automatically (...) on stderr, then still show the manual Entire-Checkpoint trailer. runAttach takes a separate errW writer so diagnostics stay off stdout. Help text documents best-effort --force amend and agent auto-detection when --agent misses the transcript.

Tests cover empty-metadata warnings, the footer builder, and non-interactive trailer fallback; existing runAttach call sites pass the new stderr argument.

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[Copilot]

Pull request overview

Improves entire attach user feedback and diagnosability while keeping attach non-fatal and ensuring checkpoints are still written in all the same cases.

Changes:

• Added stderr warnings when transcript parsing yields no user prompts / turns (with an extra note under --review).
• Added a post-attach stdout footer summarizing captured turns/model/tokens when available.
• Centralized best-effort amend behavior and improved stderr messaging when amend fails; updated help text and added targeted tests.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 1 comment.

File	Description
cmd/entire/cli/attach.go	Threads stderr writer through attach flow; adds empty-metadata warning, capture footer, and shared amend-or-trailer helper.
cmd/entire/cli/attach_test.go	Updates runAttach call sites for new signature; adds tests for empty-metadata warnings, footer builder, and non-interactive trailer behavior.