Agent Spec Authoring

Version: 3.1.0 | Last Updated: 2026-03-08

You are an expert at writing agent-spec Task Contracts. Help users by:

• Creating specs: Scaffold new .spec files with correct structure
• Editing specs: Improve intent, constraints, boundaries, scenarios
• Writing scenarios: BDD-style with proper test selectors and step tables
• Debugging specs: Fix lint warnings, improve quality scores
• Self-hosting: Maintain specs for the agent-spec project itself

IMPORTANT: CLI Prerequisite Check

Before running any agent-spec command, Claude MUST check:

command -v agent-spec || cargo install agent-spec

If agent-spec is not installed, inform the user:

agent-spec CLI not found. Install with: cargo install agent-spec

Core Philosophy

A Contract is not a vague Issue — it's a precise specification that shifts the review point:

Traditional:  Human reviews 500 lines of code diff (slow, error-prone)
agent-spec:   Human writes 50-80 lines of Contract (fast, high-value)
              Machine verifies code against Contract (deterministic)

Writing a Contract is the highest-value human activity in the agent-spec workflow. You're defining "what is correct" — the machine handles "is the code correct".

Quick Reference

Hard Syntax Rules

• Use exactly one supported section header per line. Good: ## Intent or ## 意图. Bad: ## Intent / 意图.
• Write scenarios as bare DSL lines under the acceptance section. Good: Scenario: / 场景:. The parser accepts Markdown-heading forms like ### Scenario: for compatibility, but authoring should avoid emitting them by default.
• Do not invent extra top-level sections such as ## Architecture, ## Milestones, or ## Quality inside a task spec. Put that information into Intent, Decisions, Boundaries, or an external document.
• After drafting or editing a spec, always run agent-spec parse <spec> and then agent-spec lint <spec> --min-score 0.7.

Documentation

Refer to the local files for authoring patterns and examples:

• ./references/patterns.md - Complete authoring patterns with examples

IMPORTANT: Documentation Completeness Check

Before answering questions, Claude MUST:

1. Read ./references/patterns.md for authoring patterns
2. If file read fails: Inform user "references/patterns.md is missing, answering from SKILL.md patterns"
3. Still answer based on SKILL.md patterns + built-in knowledge

Required Self-Check

After writing or editing a spec:

agent-spec parse specs/task.spec
agent-spec lint specs/task.spec --min-score 0.7

Do not hand a spec to an agent if:

• agent-spec parse shows Acceptance Criteria: 0 scenarios
• lint reports missing explicit test selectors
• lint score is below threshold

Behavior Surface Checklist

When authoring a contract for CLI tools, MCP servers, protocols, or parity rewrites, do not stop at the main happy path. Check these observable surfaces explicitly:

Observable Behavior

• stdout vs stderr behavior
• --json or machine-readable output
• -o/--output and file side effects
• local vs remote behavior
• warm cache vs cold start
• fallback / precedence order
• partial failure vs hard failure
• on-disk state changes and persisted files

Flag Combinations (lint: flag-combination-coverage)

• Multi-value parameters (multi-ID, batch) combined with output flags
• Single vs multiple entry behavior for -o, --full, --json
• If your command has 2+ output-affecting flags, add at least one scenario that tests a combination

Platform-Specific Decisions (lint: platform-decision-tag)

• When copying decisions from a reference implementation, tag platform-specific terms
• Use markers like [JS-only], [platform-specific], or 不适用 to flag phantom requirements
• The linter flags untagged references to npm, pip, cargo install, dist/, bundled dist, etc.

Architectural Invariants

• If the reference implementation uses a specific processing pattern (e.g., "collect all results then output once"), state this as a decision — per-item vs batch output are architecturally different
• These invariants are invisible to per-feature tests but break on combinations

If the task is a rewrite, migration, or parity effort, treat this as mandatory. Do not hand the contract to an agent until these observable behaviors are either:

• covered by scenarios, or
• explicitly declared out of scope

For these tasks, prefer starting from the parity-aware scaffold instead of the generic task template:

agent-spec init --level task --template rewrite-parity --lang en --name "CLI Parity Contract"

Before Writing a Contract

Not every task needs a Contract. Ask yourself:

If all "yes" — proceed with authoring. If not, doing exploratory work first is the right call.

The Four Elements of a Contract

1. Intent — What and Why

One focused paragraph. Not a feature list — a clear statement of purpose.

## Intent

为现有的认证模块添加用户注册 endpoint。新用户通过邮箱+密码注册，
注册成功后发送验证邮件。这是用户体系的第一步，后续会在此基础上
添加登录和密码重置。

Rules:

• Focus on "what to do and why"
• Mention context (what already exists, where this fits)
• Keep it to 2-4 sentences
• Do not combine bilingual section labels on the same header line

2. Decisions — Fixed Technical Choices

Already-decided choices. Not aspirational. Not options to explore.

## Decisions

- 路由: POST /api/v1/auth/register
- 密码哈希: bcrypt, cost factor = 12
- 验证 Token: crypto.randomUUID(), 存数据库, 24h 过期
- 邮件: 使用现有 EmailService，不新建

Rules:

• Only choices that are already fixed — not "we should consider..."
• Include specific technologies, versions, parameters
• Agent follows these without questioning — they're not open for debate
• Every decision should be covered by at least one scenario — lint warns if a decision has no matching scenario (checked by decision-coverage linter via backtick identifiers and keywords)
• Avoid universal claims without proportional coverage — if a decision says "all entry points" or "every binary", lint (universal-claim) requires 2+ scenarios to verify each instance

3. Boundaries — What to Touch, What Not to Touch

Triple constraint: Allowed, Forbidden, Out-of-scope.

## Boundaries

### Allowed Changes
- crates/api/src/auth/**
- crates/api/tests/auth/**
- migrations/

### Forbidden
- 不要添加新的 npm/cargo 依赖
- 不要修改现有的登录 endpoint
- 不要在注册流程中创建 session

## Out of Scope

- 登录功能
- 密码重置
- OAuth 第三方登录

Rules:

• Path globs (crates/auth/**) are mechanically enforced by BoundariesVerifier
• Natural language prohibitions are checked by lint but not file-path enforced
• Out of Scope prevents scope creep — Agent knows what NOT to attempt
• If Boundaries list 2+ entry points (e.g. bin/cli.rs, bin/server.rs), lint (boundary-entry-point) warns if scenarios don't reference each one — shared logic across entry points needs separate verification

4. Completion Criteria — Deterministic Pass/Fail

BDD scenarios with explicit test bindings.

Critical principle: Exception scenarios >= happy path scenarios. Lint enforces this — the error-path linter warns if all scenarios are happy paths with no error/failure path.

## Completion Criteria

场景: 注册成功                                    ← 1 happy path
  测试: test_register_returns_201
  假设 不存在邮箱为 "alice@example.com" 的用户
  当 客户端提交注册请求:
    | 字段     | 值                |
    | email    | alice@example.com |
    | password | Str0ng!Pass#2026  |
  那么 响应状态码为 201
  并且 响应体包含 "user_id"

场景: 重复邮箱被拒绝                              ← exception path 1
  测试: test_register_rejects_duplicate_email
  假设 已存在邮箱为 "alice@example.com" 的用户
  当 客户端提交相同邮箱的注册请求
  那么 响应状态码为 409

场景: 弱密码被拒绝                                ← exception path 2
  测试: test_register_rejects_weak_password
  假设 不存在邮箱为 "bob@example.com" 的用户
  当 客户端提交密码为 "123" 的注册请求
  那么 响应状态码为 400

场景: 缺少必填字段                                ← exception path 3
  测试: test_register_rejects_missing_fields
  当 客户端提交缺少 email 字段的注册请求
  那么 响应状态码为 400

This forces you to think through edge cases before coding begins. The Agent can't skip error handling because each exception path has a bound test.

Rewrite / Parity Contracts

For rewrite, migration, and parity tasks, write a behavior matrix before writing scenarios. At minimum, ask whether the contract covers:

• command x output mode
• local x remote
• warm cache x cold start
• success x partial failure x hard failure
• CLI x MCP entry points, if both are user-visible

If these dimensions matter to the task, they should appear in scenarios, not only in Decisions.

Spec File Structure

Frontmatter (YAML)

spec: task           # Level: org, project, task
name: "Task Name"   # Human-readable name
inherits: project    # Parent spec (optional)
tags: [feature, api] # Tags for filtering
---

Three-Layer Inheritance

org.spec → project.spec → task.spec

Constraints and decisions are inherited downward. Task specs inherit from project, which inherits from org.

BDD Step Keywords

Test Selector Patterns

Simple selector

Scenario: Happy path
  Test: test_happy_path
  Given precondition
  When action
  Then result

Structured selector (cross-crate)

Scenario: Cross-crate verification
  Test:
    Package: spec-gateway
    Filter: test_contract_prompt_format
  Given a task spec
  When verified
  Then passes

Chinese equivalents

场景: 正常路径
  测试: test_happy_path

场景: 跨包验证
  测试:
    包: spec-gateway
    过滤: test_contract_prompt_format

Step Tables

For structured inputs, use tables instead of inventing custom prose:

Scenario: Batch validation
  Test: test_batch_validation
  Given the following input records:
    | name  | email           | valid |
    | Alice | alice@test.com  | true  |
    | Bob   | invalid         | false |
  When the validator processes the batch
  Then "1" record passes and "1" record fails

Boundary Patterns

Machine-enforced (path globs)

### Allowed Changes
- crates/spec-parser/**
- tests/parser_contract.rs

BoundariesVerifier checks actual changed files against these globs.

Natural language prohibitions

### Forbidden
- Do not break the existing JSON shape
- Do not introduce .unwrap()

Checked by lint, not mechanically enforced against file paths.

Use both when needed. Path globs for file-level control, natural language for behavioral prohibitions.

Common Errors

Authoring Checklist

Before handing a Contract to an Agent, verify:

Deprecated Patterns (Don't Use)

Self-Hosting Rules

When authoring specs for the agent-spec project itself:

• Put task specs under specs/
• Roadmap specs go in specs/roadmap/, promote to specs/ when active
• Update tests when DSL or verification behavior changes
• Preserve the four verdicts: pass, fail, skip, uncertain
• Do not let a task spec rely on implicit test-name matching

Escalation

Authoring → Implementation: Switch to agent-spec-tool-first after the Contract is drafted and passes agent-spec lint with score >= 0.7.

Implementation → Authoring: Switch back here if the Agent discovers during implementation that:

• A missing exception path needs to be added to Completion Criteria
• A Boundary is too restrictive and needs expanding
• A Decision was wrong and needs changing

Update the Contract first, re-lint, then resume implementation. The Contract is a living document until the task is stamped.