Seed Scratch Manager briefs from the .md file only; never paste them (CROW-1327)

[dgershman]

Closes #1327

Problem

todo explore / todo ticket wrote the brief to $TMPDIR/crow-explore-<session>.md and launched the Manager with it as argv (CROW-1237) — then also pasted the full multi-line brief via sendToManager, retried Enter, and re-pasted it when the agent looked idle. On a slow SessionStart that second copy landed offset (2026-10-13 repro: the Manager's prompt began at Scratch item, preamble gone).

Change

The .md file is the single source of truth for the seed.

• Fresh Manager: seeded by its launch command alone. Nothing is pasted afterwards. seeded = brief file written && pane appeared.
• Live Manager (re-Explore, Ticket on an alive Manager): rewrite the file and type one line — Read and follow the instructions in <path>.
• sendToManager (pointer line + todo talk only) types one line and retries a bare Enter at most once. The full re-paste and the accepted-prompt polling (promptWasAccepted, agentAnnouncePolls) are removed — the latter were only there to guess whether the argv seed had started.
• New TodoRPC.writeBriefFile / briefPointer / briefDelivery; exploreSeedLaunchCommand uses writeBriefFile.
• Warnings on seeded: false now say what actually failed instead of "still starting".
• Docs: CLAUDE.md, docs/cli-reference.md, ADR 0026 wording, CHANGELOG.

Tests

• freshManagerSeedsViaArgvWithNoFollowUpPaste — for Claude Code, Cursor, Codex, Grok, OpenCode: the file holds the complete brief (first line intact), the launch command reads it, delivery is .launchArgv (no paste).
• aliveManagerGetsOnlyThePointerLine — delivery is a single-line pointer, never brief text.
• unwrittenBriefDeliversNothing.
• swift test --package-path Packages/CrowEngine --filter TodoRPCSupportTests — 21/21 pass. swift build --package-path Packages/CrowDaemon clean (CrowDaemon tests not run on host — they boot crowd).

Not verified

Repeated cold launches across all five harnesses in a live Crow (the ticket's manual acceptance check) — please run crow todo ticket / todo explore a few times per harness after merge.

🤖 Generated with Claude Code

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[dhilgaertner]

Code & Security Review

Critical Issues (if any)

None.

Architecture / Existing Patterns

• Existing pathway: CROW-1237 argv seed — ManagerSessionController.exploreSeedLaunchCommand writes $TMPDIR/crow-explore-<session>.md and wraps the Manager launch with ShellLaunchArgs.evalPromptLaunch (same shape as jobs / #408). sendToManager in TodoRPCHandlers.swift was the leftover paste fallback after that seed.
• This change extends that path instead of replacing it. Fresh Managers stay argv-only; live Managers get a one-line pointer through the existing typer. Dropping promptWasAccepted and agentAnnouncePolls is the right cut: those existed to guess whether the argv seed had started so a second copy of the brief could be skipped or re-pasted.
• Green: #1327 asked for a pointer fallback on a fresh Manager if a harness ignores positional argv. This PR does not add that arm — it matches the job launch (argv or nothing). The description already marks repeated cold launches across the five harnesses as unverified.

Security Review

Strengths:

• The brief path is NSTemporaryDirectory() plus a session UUID (TodoRPCSupport.swift explorePromptPath), not derived from scratch text, so the pointer line cannot be steered at an attacker-chosen file.
• writeBriefFile refuses whitespace-only bodies and writes atomically. Live Managers never put the multi-line brief (backticks, gh issue create, crow todo link) into a TUI that might still be zsh.
• sendToManager no longer re-sends the payload. A second full paste was the offset/truncation failure this ticket exists to stop.

Concerns:

• None that are defects in this diff. managerTerminal still takes appState.terminals[sessionID]?.first rather than isAgentSurface; that is pre-existing on the talk path. A one-line pointer landing in a still-starting shell is safer than the old 20-line brief.

Code Quality

• Green: freshManagerSeedsViaArgvWithNoFollowUpPaste in TodoRPCSupportTests.swift checks exploreSeedLaunchCommand and briefDelivery == .launchArgv. It does not run openScratchManager, which is the site that used to call sendToManager(..., text: brief). The handler change is the actual "no follow-up paste" guarantee.
• swift test --package-path Packages/CrowEngine --filter TodoRPCSupportTests — 21/21 passed. swift build --package-path Packages/CrowDaemon — clean.

Summary Table

Color	Meaning	Verdict effect
Red	Must fix	Request changes
Yellow	Should fix	Request changes
Green	Consider	Approve allowed

Recommendation: Approve — driven by 0 Red, 0 Yellow, 2 Green findings.

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🐦‍⬛ Reviewed by Crow via Cursor