CLI: surrogate-safe truncation for task-plan objective + verify commands (remaining raw slices) #874

Self-discovery (undirected maintainer review pass). Left unclaimed for the next natural tick.

sourceType

Self-discovery (repository maintainer review of qwen-code-dev-bot/oh-my-cli).

sourceLinkOrEvidence

• src/task-plan.ts:63 — redactObjective: return redactSecrets(task ?? "").text.trim().slice(0, MAX_OBJECTIVE); (MAX_OBJECTIVE = 500) — raw slice of the untrusted user objective (the interface documents it as "untrusted input; redacted and bounded").
• src/task-plan.ts:73 — deriveVerifyCommands: commands.push(redactSecrets(ref.command).text.slice(0, MAX_COMMAND_LEN)); (MAX_COMMAND_LEN = 120) — raw slice of the derived verify command.
• Consumed via the exported planTask (src/task-plan.ts:127), so both are reachable and testable.

Minimal reproduction: planTask({ task: "a".repeat(499) + "🚀 tail", workspace }) yields plan.objective ending in an orphaned high surrogate — the raw slice(0, 500) keeps the rocket's high surrogate (index 499) while cutting its low partner (index 500). The same shape applies to a derived verify command straddling the MAX_COMMAND_LEN bound.

problemStatement

task-plan.ts still truncates with a raw String.prototype.slice(0, N) in two places: redactObjective (the untrusted task objective) and deriveVerifyCommands (derived verify commands). When an astral character straddles the bound, the kept prefix ends in an orphaned surrogate. This is the same class as the objective truncation fixed in session-goal.ts (#868) and lags the safeCutEnd convention established by #812/#821 and extended through #860/#868/#870.

userValue

Task-plan objectives and derived verify commands containing emoji/astral characters truncate cleanly instead of ending in an unpaired surrogate — consistent with every other truncation path in the CLI.

scope

• src/task-plan.ts redactObjective: cut via safeCutEnd (import from ./text-cut.js).
• src/task-plan.ts deriveVerifyCommands: cut the command via safeCutEnd.
• Keep the MAX_OBJECTIVE / MAX_COMMAND_LEN bounds and redaction unchanged.
• Red→green regression tests for both.

nonGoals

• Not changing the bounds, redaction, plan structure, or phase derivation.
• The remaining raw command/name display slices in repo-context.ts (redactName/redactCommand), run-bottleneck.ts (safeName), and run-failure-taxonomy.ts are out of scope here; file separately if warranted.

acceptanceCriteria

• Given a task objective / verify command whose astral character straddles the truncation bound, the truncated result contains no orphaned surrogate (regex [\ud800-\udbff](?![\udc00-\udfff])|(?<![\ud800-\udbff])[\udc00-\udfff] does not match) and still respects the length bound.
• ASCII-only objectives/commands at or below the bound are unchanged (existing "bounds the objective length" test still passes).

testPlan

• Regression tests in tests/unit/task-plan.test.ts: surrogate-straddle for the objective (via planTask) and for a derived verify command (via a package.json script straddling MAX_COMMAND_LEN); plus the existing ASCII bound case.
• Red→green: reverting the two cuts to raw slice makes the new tests fail; restoring safeCutEnd turns them green.
• Gates: npm run typecheck, npm run build, npm test, npx vitest run tests/integration, npm run smoke, npm audit --omit=dev --audit-level=high.

dogfoodPlan

After merge, run npx vitest run tests/unit/task-plan.test.ts tests/unit/text-cut.test.ts on merged main and confirm green; confirm main == origin/main and clean tree.

riskAndSecurityNotes

Behavior surface unchanged except surrogate safety at the cut; redaction and plan semantics are untouched. Tests use inert local fixtures (no secrets). No new attack surface.

duplicateSearchEvidence

• gh search issues "task-plan truncat" / "redactObjective" / "task-plan surrogate" -> no results.
• gh search issues "deriveVerifyCommands" -> only Task verification: run the canonical verify commands and emit a bounded, redacted, head-bound pass/fail verdict #66 (closed), the original task-verification feature; no truncation/surrogate issue.
• CLI: surrogate-safe truncation for goal objective + workspace-memory text (remaining raw slices deferred by #860) #868 fixed the analogous session-goal.ts objective truncation; task-plan.ts is a distinct module not covered by CLI: surrogate-safe tail truncation for task-verify failure output and failure receipts #860/CLI: surrogate-safe truncation for goal objective + workspace-memory text (remaining raw slices deferred by #860) #868/CLI: surrogate-safe truncation for hook tool-arg bounds + task-runtime detail (remaining raw slices) #870.

parentChildRelationship

Standalone leaf subtask; no parent roadmap item required and no children anticipated.

dependencyOrder

No dependencies; dependency-ready. Self-contained change to src/task-plan.ts (+ tests) using the existing text-cut.ts helper.