Sprint Contract

Sprint Contract — Multi-Agent Quality System

Based on Anthropic's harness design for long-running apps: separate the agent doing the work from the agent judging it.

Core Principle

Never let the builder evaluate their own work on complex tasks. LLMs reliably praise their own output — even when it's mediocre. An independent evaluator, tuned to be skeptical, catches what self-evaluation misses.

Architecture

Planner (you/human) → Generator (sub-agent) → Evaluator (independent sub-agent)
     ↑                                              |
     └──────────── feedback loop ←──────────────────┘

Workflow

1. Write a BRIEF.md with Sprint Contract

Every task gets a BRIEF.md. The Sprint Contract section is mandatory — it lists specific, testable completion criteria.

# Task Brief
Background
[Why this task exists]
Objective
[What to build/fix]
Sprint Contract (Completion Criteria)
[ ] Criterion 1 (specific, verifiable)
[ ] Criterion 2
[ ] ...
⚠️ Write criteria specific to THIS task. No generic checklists.
Related Files
[File paths relevant to the task]
Constraints
[Tech stack, prior decisions, known pitfalls]
Handoff Requirements
Write a HANDOFF.md when done, containing:
What was done (file change list)
Design decisions made (and why)
What's left / known issues
Everything needed for reporting to the human

2. Spawn Generator (Builder)

The generator receives the BRIEF.md and builds against the Sprint Contract. Key rules for the generator prompt:

3. Spawn Evaluator (Independent QA)

After the generator finishes, spawn a separate agent as evaluator. The evaluator prompt must include:

The Sprint Contract — copied from BRIEF.md, to verify each criterion.

4 Evaluation Dimensions (select what's relevant):

| Dimension | What to check | |-----------|--------------| | Functional completeness | Every Sprint Contract criterion passes | | User experience | Flow is intuitive, no dead ends | | Visual quality | Layout, spacing, colors are professional | | Code/content quality | No errors, clean logic, no regressions |

The critical prompt line: > "Your job is to find problems, not to praise. If everything looks fine, you probably didn't test carefully enough. Report issues honestly — better a false alarm than a missed bug."

4. Decision Gate

Based on evaluator feedback:

When to Use Each Mode

| Task complexity | Generator | Evaluator | Example | |----------------|-----------|-----------|---------| | Simple (< 30 min) | Sub-agent | Self-evaluate, mark "⚠️ untested" | Fix a typo, update config | | Medium (30 min - 2 hr) | Sub-agent | Independent sub-agent | New feature, bug fix | | Complex (2+ hr) | Claude Code / ACP | Independent sub-agent + human review | Architecture change, new project |

Sprint Contract Examples

See references/contract-examples.md for project-specific contract templates.

Key Insights from Anthropic's Research

1. File-based communication — Agents talk through files (BRIEF.md, HANDOFF.md), not conversation 2. Evaluator calibration — Default LLMs are too lenient; explicitly prompt for skepticism 3. Sprint scoping — One feature at a time; don't bundle unrelated work 4. Opus 4.6 + 1M context — Context anxiety is gone; sprint decomposition is less critical, but evaluator still adds value at task boundaries 5. Evaluation criteria shape output — The wording of your criteria directly steers what the generator produces

[Tech stack, prior decisions, known pitfalls]