[Vasanthdev2004]

What changed

• specialist.BuildResumeArgs passes --calling-session-id and --calling-tool-use-id, the same flags the fresh run passes. runResume fills them from the Task call.
• New sessions.ExecResumable(session, callingSessionID, tag). Kinds IsResumableKind accepts stay resumable. A child session is resumable only when the calling session is the child's recorded parent and the tag is the child's own tag.
• Both exec checks use it: the CLI preflight in internal/cli/exec_sessions.go and sessions.PrepareExec. They were two separate kind checks before, which is why a fix in PrepareExec alone still failed.

Why

Task resume runs zero exec --resume <child> on the child session that the fresh run created (kind child, tag specialist). Since #748, exec refuses every child, so every Task resume failed with Zero session is not resumable: <id>. The specialist tests launch a fake binary, so nothing caught it. docs/SPECIALISTS.md already lists Task resume as supported.

#748's intent is kept. A plain zero exec --resume <child> is still refused, and so is a resume that names another parent or another tag. Side sessions such as /btw are never children, so they stay out. ResumeLatest and the resume pickers still use IsResumableKind and are unchanged.

Linked issue

Fixes #1209

Verification

• TestTaskResumeContinuesTheSpecialistChildThroughExec (internal/cli) runs the Task tool's real arguments through the real exec entry point in process, with no fake binary. The fresh run creates the child, the resume continues it (the provider sees Continuing Zero session child_task. and no new session is created), and two hand-written resumes are still refused. On main the resume fails: the child exits 2 with Zero session is not resumable: child_task.
• TestPrepareExecResumesAChildOnlyForItsOwner (internal/sessions) covers the owner resume and six refusals: plain, tag only, caller only, another parent, another tag, and a side session. On main it fails with owner resume of a child: Zero session is not resumable: child_task.
• 10 mutations, all caught. Each mutation does one of these: drops the resume flag, drops the parent from runResume, refuses every child, skips the parent match (unit and end to end), skips the tag match, lets side sessions in, or puts the old kind check back in the preflight or PrepareExec.
• gofmt, go vet ./... for windows, linux and darwin, go test ./..., -race on sessions and specialist, release build and smoke, golangci-lint v2.12.2 (unused, ineffassign, staticcheck) on the touched packages for windows, linux and darwin, and git diff --check.
• govulncheck reports GO-2026-6859 here, as it does on main. fix: bump Go to 1.26.11 for GO-2026-6859 #1218 fixes that.

Summary by CodeRabbit

• Bug Fixes
  • Task resume now continues an existing specialist child session when resumed by its owning parent with the matching tag, preserving the child’s history and avoiding creation of an extra session.
  • Child sessions remain unavailable for direct resume or resume by a different parent.

[github-actions]

Zero automated PR review

Verdict: No blockers found

Blockers

• None found.

Validation

• [pass] Diff hygiene: git diff --check
• [pass] Tests: go test ./...
• [pass] Build: go run ./cmd/zero-release build
• [pass] Smoke build: go run ./cmd/zero-release smoke

Scope

Head: 21cd7ae48018
Changed files (5): internal/cli/exec_sessions.go, internal/cli/exec_task_resume_test.go, internal/sessions/exec_resume_owner_test.go, internal/sessions/exec_session.go, internal/specialist/exec.go

This deterministic review checks validation status and basic diff hygiene. A human reviewer still owns product judgment and design quality.

[coderabbitai]

Walkthrough

Specialist Task resume now passes parent context to exec. Exec accepts a child session when its caller ID and tag match the session metadata. Tests cover successful Task resume and rejected direct, mismatched, missing-context, and side-session resumes.

Changes

Specialist Task resume

Layer / File(s)	Summary
Pass parent context to specialist resume internal/specialist/exec.go, internal/cli/exec_task_resume_test.go	BuildResumeArgsInput accepts parent session and tool-use IDs. runResume passes them through, and BuildResumeArgs adds nonblank values to the child resume arguments. The in-process integration test checks that Task resume continues the existing child session without creating another session.
Validate child-session ownership internal/sessions/exec_session.go, internal/cli/exec_sessions.go, internal/sessions/exec_resume_owner_test.go, internal/cli/exec_task_resume_test.go	ExecResumable retains the existing resumable kinds and permits child sessions only when the trimmed caller ID and tag match the child metadata. Exec uses this check during resume. Tests cover matching ownership and tag, as well as rejected direct, missing, mismatched, and side-session cases.

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

Sequence Diagram(s)

sequenceDiagram
  participant Task as Specialist Task
  participant runResume
  participant BuildResumeArgs
  participant Exec as zero exec
  participant ExecResumable
  Task->>runResume: Resume with parent session and tool-use IDs
  runResume->>BuildResumeArgs: Pass parent IDs
  BuildResumeArgs->>Exec: Add calling-session and calling-tool-use arguments
  Exec->>ExecResumable: Check session, calling session ID, and tag
  ExecResumable-->>Exec: Return resumability result

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Suggested reviewers: anandh8x

Merge Risk: Minimal · up to 21cd7

Task resume can now continue its own specialist child, and other resume attempts are still refused. No merge-blocking risk was found.

Pre-merge checks: 4 · 1

Failed checks: 1 warning

Check name	Status	Explanation	Resolution
Docstring Coverage		Docstring coverage is 60.00% which is insufficient. The required threshold is 80.00%. Docstring coverage is scoped to functions touched by this diff with cyclomatic complexity of at least 2. Documenta…	Write docstrings for the functions missing them to satisfy the coverage threshold.

Passed checks: 4 passed

Check name	Status	Explanation
Description Check		Check skipped - CodeRabbit’s high-level summary is enabled.
Title check		The title clearly and concisely describes the main change: allowing Task resume to continue its own specialist child.
Linked Issues check		Issue #1209 requires Task resume to continue its own specialist child through the real exec path. BuildResumeArgs and runResume pass the parent session ID and tool-use ID. ExecResumable permits …
Out of Scope Changes check		The changed implementation, CLI preflight, specialist argument propagation, and tests directly support issue #1209. The tests validate the required authorization boundaries, including side-session exc…

Full details: Linked Issues check

Explanation

Issue #1209 requires Task resume to continue its own specialist child through the real exec path. BuildResumeArgs and runResume pass the parent session ID and tool-use ID. ExecResumable permits a child only when the calling session matches the recorded parent and the tag matches the child tag. Both the CLI preflight and sessions.PrepareExec use this check. The integration test exercises the real in-process exec path and verifies continuation without a new session. It also verifies plain and wrong-parent resumes remain refused. The sessions test covers the owner and refusal cases. The change fixes behavior, so no documentation change is required.

Full details: Out of Scope Changes check

Explanation

The changed implementation, CLI preflight, specialist argument propagation, and tests directly support issue #1209. The tests validate the required authorization boundaries, including side-session exclusion and mismatched parent or tag refusal. No unrelated change is demonstrated by the supplied whole-PR summary.

Full details: Docstring Coverage

Explanation

Docstring coverage is 60.00% which is insufficient. The required threshold is 80.00%. Docstring coverage is scoped to functions touched by this diff with cyclomatic complexity of at least 2. Documentation-only edits and deletions within surviving functions are included; unchanged diff context and fully deleted functions are excluded. Analyzed 5 functions across 5 files.

Resolution

Write docstrings for the functions missing them to satisfy the coverage threshold.

Finishing Touches

Generate docstrings

• Commit to this branch
• Create a new PR

Generate unit tests (beta)

• Commit to this branch
• Create a new PR

• Autofix · Keep fixing CodeRabbit findings and required CI, and resolving merge conflicts

[coderabbitai]

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only still-valid issues, skip the rest with a brief reason, keep changes
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Failed pre-merge checks:
- Docstring Coverage:
Write docstrings for the functions missing them to satisfy the coverage
threshold.

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Review info

Run configuration

• Source mode: Auto
• Repository: Twigpine/zero
• Branch: fix/task-resume-specialist-child
• File: .coderabbit.yaml
• Commit: 21cd7ae
• Layers: Repository YAML
• Review profile: CHILL
• Plan: Essentials
• Run ID: de6dd146-12e8-4bbf-b684-5fbd87a281e0

Commits

Reviewing files that changed from the base of the PR and between 17fcd26 and 21cd7ae.

Files selected for processing: 5

• internal/cli/exec_sessions.go
• internal/cli/exec_task_resume_test.go
• internal/sessions/exec_resume_owner_test.go
• internal/sessions/exec_session.go
• internal/specialist/exec.go

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