| Role | Job | Watch for |
|---|
| Coordinator | Decomposes, delegates, aggregates | Earns its seat only when subtasks cannot be predicted |
| Subagent | Works one slice in an isolated context | Inherits none of the parent’s work; the brief is its whole world |
| Seam | Where context, failures, and sources cross | Every seam must justify itself, then be engineered |
Channel in from the coordinator: the delegation prompt. Channel out: the final message. Nothing else crosses.
| Element | Answers | Rosa’s pricing surveyor |
|---|
| Objective | What job, and why | Survey regional cargo-gear prices for the second store |
| Output format | What comes back, in what shape | Category, price band, seller, source URL per entry |
| Tools and sources | Where to look, what to prefer | Web search; seller pages over aggregators |
| Boundaries | What not to do; who owns the rest | Prices only; competitor strategy belongs to the scanner |
Rule: no pronouns, no “as discussed.” If it is not in the brief, it does not exist.
| Failure mode | Symptom | Test before spawning |
|---|
| Gap | Confident report about a smaller question | What part of the task belongs to nobody? |
| Overlap | Duplicated work, conflicting versions of one fact | Which two briefs could return the same fact? |
Goal: everything covered, each piece owned once. Shared territory names one owner in both briefs.
| Question | Answer | Action |
|---|
| Does brief B need brief A’s output? | No | Spawn together |
| Does brief B need brief A’s output? | Yes | Chain; paste A’s output into B’s brief |
Cost note: parallelism buys back latency (up to 90 percent, per Anthropic), never tokens. Multi-agent runs cost many times a single chat.
| Field | Contains |
|---|
| What failed | The wall, named, with evidence of attempts |
| What was attempted | Routes tried, so nobody retries them blindly |
| Partial results | What survived, with sources attached |
| Not covered | The gap, stated as a gap |
Coordinator’s three moves: retry (transient), reroute (new subagent or source), proceed with the gap annotated.
Anti-patterns: the silent swallow (failure laundered into an invisible gap) and the kill switch (one failure discards everyone’s work).
| Rule | Because |
|---|
| Claim and source travel as one unit | Summarization strips sources by default |
| Every output format demands sources | The coordinator cannot recover a URL it never received |
| Cite in the final synthesis | A report should ship with its receipts |
| Pitfall | Correction |
|---|
| Delegating as if the subagent were in the room | Paste in everything needed, every time |
| Decomposing by what is easy to name | Test for gaps and overlaps against the original task |
| One schedule for everything | Dependency test per pair of subtasks |
| Prose apologies as failure reports | Require the structured form |
| Synthesis that strips sources | Claim-plus-source pairs in every format |
| Line | Meaning |
|---|
| A subagent inherits none of your context; the brief is its world | Write for a fresh desk |
| A failure is a finding | Structure it so the coordinator can act |
| A claim without its source arrives as a rumor | Attribution dies in the middle hop |
