Closes #1784.

Several gbrain subcommands gated their primary output (or the amount of work they did) on process.stdout.isTTY. Run them from a subagent / pipe / cron and they silently switched branches — JSON when you wanted human text, or nothing useful. The read paths (get/list/search/query) were already clean; this fixes the commands that weren't, and establishes the repo rule across them: human by default, JSON only with --json; a terminal controls cosmetics (live dashboard, color, loop cadence), never what data prints.

What's in this PR (5 commits)

feat(eval): cycle-default — new src/core/eval/cycle-default.ts: one source of truth for the TTY=3 / non-TTY=1 cycle default + the banner-suffix helper. Library-core stays TTY-agnostic; the CLI layer owns the TTY upgrade + annotation.

fix(jobs): decouple 'jobs watch' — splits two tangled axes: --json (FORMAT) and --follow (LOOP, default isTTY && !json). Non-TTY now prints one human snapshot and exits instead of an endless JSON stream; --follow opts back into the continuous stream. TTY live dashboard unchanged. Pure resolveWatchMode(opts, isTTY) extracted so the full matrix is unit-tested. JSDoc rewritten (the false "stdin close quits" claim corrected).

fix(reindex): human cost-refusal — reindex-code still refuses to re-embed non-interactively without --yes (exit 2, no spend), but the refusal is now human text unless --json is passed. Extracted into pure buildCostRefusal().

fix(eval): annotate non-interactive defaults — eval cross-modal + eval takes-quality (run + regress) annotate their existing banner when the cycle count is the silent non-TTY default (cycles: 1 (non-interactive default; --cycles N for more)). eval suspected-contradictions does the same for its $1 non-TTY budget (added budgetUsdExplicit so the annotation is accurate). takes-quality-eval/runner.ts core defaults to the constant (no process.stdout.isTTY read in library code).

chore: bump version and changelog — VERSION + package.json → 0.42.15.0, CHANGELOG, TODOS.

Out of scope (filed as TODOs)

• sync.ts:2491 has the byte-identical cost-refusal-format bug — documented gate, deserves its own change.
• agent/book-mirror follow: isTTY are the correct loop-gate (identical data, overridable), not bugs.
• jobs --help has no subcommand list (pre-existing gap).

Tests

• New: test/eval/cycle-default.test.ts, test/reindex-cost-refusal.test.ts, test/eval-suspected-contradictions-budget-default.test.ts, test/jobs-watch-mode.test.ts (the format×loop matrix), test/e2e/non-tty-output.serial.test.ts (the cmd </dev/null contract the issue asked for).
• 32 new/related unit + e2e pass; existing jobs-watch + takes-quality tests pass; bun run verify 29/29 green.

Review

• /plan-eng-review CLEAR; codex outside-voice on the plan (3 material findings adopted) and an adversarial pass on the final diff (1 finding — TTY+--json looping forever — fixed via resolveWatchMode + the matrix test before this PR).

🤖 Generated with Claude Code

Documentation

• CLAUDE.md — Key Files notes added/updated for the v0.42.15.0 wave: jobs.ts (the jobs watch format/loop split + resolveWatchMode + the new cycle-default.ts module), reindex-code.ts (human cost-refusal + buildCostRefusal), eval-cross-modal.ts (cycle/budget banner annotation + resolveCycleDefault/cycleDefaultSuffix).
• CHANGELOG.md — ## [0.42.15.0] entry (ELI10 lead + "To take advantage" block).
• TODOS.md — filed the two deferred follow-ups (sync.ts:2491 human refusal; jobs --help subcommand table).
• llms-full.txt — regenerated from CLAUDE.md (build:llms test green).
• Coverage: all shipped surface (the jobs watch flags, the reindex refusal format, the eval annotations, cycle-default.ts) has reference coverage in CLAUDE.md. No README change needed (CLI-flag-level behavior). No architecture-diagram drift.