Hunter B
5815f94f0b
State the v0.8.60 direction plainly: sub-agent is role and UX vocabulary, while durable detached work should use the fleet-backed worker lifecycle. Document the current agent_open path as compatibility until retry, receipt, and ledger semantics are unified with Fleet. Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
144 lines
7.7 KiB
Markdown
144 lines
7.7 KiB
Markdown
# The CodeWhale Agent Runtime — one durable substrate, familiar launchers
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This document explains how sub-agents, the headless `exec` path, and Agent Fleet
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relate. It exists because these had drifted into *two* parallel "worker"
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systems, and the fix is to make the **fleet-backed worker run** the durable
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primitive. "Sub-agent" remains useful product vocabulary for a nested role, but
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it must not imply a separate execution substrate with weaker lifecycle
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semantics. It also answers the open direction question in #2972 ("how much
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Claude Code convergence is right?").
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## The core idea
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There is exactly **one** thing that runs detached agent work: a **headless agent
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runtime** wrapped in a durable worker lifecycle. It is a model loop with the
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full (policy-gated) tool surface that can, in turn, delegate child work through
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the same lifecycle. Everything else is just a different way to *launch* that one
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runtime, or a different way to *observe* it.
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```
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┌───────────────────────────────┐
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│ headless agent runtime │
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│ (full tools + can sub-spawn) │
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└───────────────────────────────┘
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▲ ▲ ▲
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launches │ │ │ launches
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│ │ │
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┌────────────┴───┐ ┌───────┴────────┐ ┌──┴───────────────────┐
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│ TUI turn │ │ `codewhale │ │ Agent Fleet │
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│ (interactive, │ │ exec` │ │ (durable: ledger, │
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│ in-process) │ │ (headless CLI,│ │ scheduler, SSH, │
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│ │ │ anyone/any- │ │ alerts) — launches │
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│ │ │ time) │ │ `codewhale exec` │
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└────────────────┘ └────────────────┘ │ per worker │
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└───────────────────────┘
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```
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- A **sub-agent** is the user-facing name for a *nested assignment* with a role
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(`explore`, `review`, `implementer`, `verifier`, ...). It should be backed by
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the same worker run lifecycle as fleet. `agent_open` is the compatibility
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launcher, not a second runtime.
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- **`codewhale exec`** is the headless front door: usable by anyone at any time
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(CI, scripts, another agent), full tools, emits a `stream-json` event stream,
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and can spawn sub-agents. It is *the* runtime with a CLI on it.
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- A **fleet worker** *is* a `codewhale exec` run that the fleet launches and
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tracks durably — locally as a subprocess, or remotely as
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`ssh host … codewhale exec …`. The fleet does not re-implement execution; it
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adds **orchestration** (durable ledger, scheduling/leasing/retry, host
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transport, alert escalation) *over* the one runtime.
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So "fleet vs sub-agent" is not two categories. It is **the same headless run**:
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Fleet is the durable control plane, while sub-agent is the role/UX vocabulary
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for a nested worker.
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## The cutover rule
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If a detached `agent_open` child can fail on a one-off provider timeout with no
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retry while an equivalent fleet worker would retry and preserve ledger evidence,
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then the cutover is incomplete. Treat that as a CodeWhale runtime gap, not as
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normal "sub-agent behavior".
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The target rule is:
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- durable or long-running work goes through the fleet worker lifecycle;
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- `agent_open` may stay as the friendly nested-agent API, but it should enqueue
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or observe a fleet-backed worker run instead of owning an independent
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lifecycle;
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- in-process children are allowed only as a small compatibility/latency
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optimization, and they must expose the same terminal states, retry semantics,
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receipts, and inspection handles as the fleet path.
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In product language it is fine to say "open a sub-agent". In architecture
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language that means "start a nested fleet worker with this role".
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## Why this shape (and why it fixes the lag)
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The motivating problem: spawning many in-process sub-agents made the TUI lag,
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because each child cloned a heavy runtime and rebuilt the whole tool registry,
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*and* the TUI rendered a full card/transcript per child.
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Surveying Claude Code, Codex, and Kimi, the thing that keeps an orchestrator
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light at high fanout is **not** a process boundary — all three run sub-agents
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in-process. It is **isolation + a compact event stream**:
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- a child's transcript **never** flows back into the parent — the parent gets a
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result summary and a small lifecycle event stream;
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- the UI renders **counts** (`2 running / 3 done`), not a child session per
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worker;
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- each worker's tool surface is built directly from a **role/capability
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profile**, not "build everything then filter".
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"Headless" therefore means *the execution is not shaped like the UI* — it does
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**not** mean fewer abilities. A headless worker keeps the full toolset and can
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spawn sub-agents.
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When the work also needs to be **durable** (survive the TUI closing, a laptop
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sleeping) or **remote** (SSH), the fleet runs the worker out-of-process as
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`codewhale exec`. The heavy construction then lives in another process entirely,
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so the orchestrator stays smooth regardless of fanout, and the run survives
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restarts — the day-scale autonomy goal of #3154.
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## One recursion axis
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A worker runs at `spawn_depth = 0` and may spawn children while
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`spawn_depth + 1 ≤ max_spawn_depth`, so a budget of `N` affords `N` nested
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delegation levels. Sub-agents and fleet workers share **one** axis, sourced from
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`codewhale_config`:
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- `DEFAULT_SPAWN_DEPTH = 3` — the default budget for both standalone sub-agents
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and fleet workers (so they cannot drift into "two moving targets");
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- `MAX_SPAWN_DEPTH_CEILING = 3` — the hard cap that every configured value
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(fleet `max_spawn_depth`, `agent_open`'s `max_depth`) clamps to.
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The root worker always runs even at budget 0; the budget gates *child*
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delegation. The default affords at least three nested levels.
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## Event vocabulary
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The fleet ledger persists the worker's own event stream rather than a separate,
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simulated taxonomy. `codewhale exec --output-format stream-json` emits
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`{"type": "content" | "tool_use" | "tool_result" | "metadata" | "done" |
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"error"}` lines, which map onto the fleet ledger's `FleetWorkerEventPayload`
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(`RunningTool`, `Running`, `Completed`, `Failed`, …). One vocabulary, two
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surfaces.
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## Convergence with Claude Code (#2972)
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CodeWhale should converge with Claude Code on **shape**, not on branding:
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- **Adopt**: a headless runtime with a real CLI/SDK front door; sub-agents as
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isolated runs that return summaries (not transcripts); a compact, event-driven
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fanout projection; capability/role tool profiles; the skills ecosystem
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(#2743); structured run receipts.
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- **Keep distinct**: CodeWhale branding and first-class DeepSeek/GLM/MiniMax/
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multi-provider support; the local-first **Agent Fleet** (durable, SSH-capable
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orchestration) as CodeWhale's own layer above the shared runtime; WhaleFlow as
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the orchestration overlay.
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- **Do not** fork execution semantics per surface. The TUI, `agent_open`,
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`exec`, the Runtime API, and the fleet must all drive the *same* runtime and
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observe the *same* event stream — divergence there is what produced the "two
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moving targets" this document exists to prevent.
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The litmus test for any new agent surface: *does it launch and observe the one
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runtime, or does it invent a second one?* Only the former is allowed.
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