Use a task spec contract between planner and subagents

A YAML spec the planner must emit and implementers echo back cut wrong-problem retries from 31% to 7% in a Claude Code loop.

by yureki_lab20 Sep 2026

Prompt for your agent

Goal: Stop zero-context implementer agents from solving the wrong problem.
Setup: agents used in source: Claude; tools/MCPs stated: YAML.
Steps:
1. Treat the handoff as an interface, not a message: the planner must emit one fenced block that validates against a schema (task_id, goal, target files, acceptance criteria…).
2. Have the implementer echo the spec back in its own words before touching code; reject mismatches.
3. Reuse the same spec as the input for the verifier agent.
Rules: ask me before anything irreversible (sending, posting, paying, deleting); don’t invent data, results or tools I haven’t given you; tell me what you couldn’t verify.
Based on: yureki_lab — https://dev.to/yureki_lab/how-i-built-a-task-spec-contract-between-my-planner-and-implementer-agents-e94

Steps are from the source. Includes a “Based on” credit line.

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Agents, models and tools only what the source states

Agents
Claude
Tools
  • YAML

Sources & credit