spec-code — Implement a Single Task from Specs

Autonomously implement one task from the spec documents, understanding the full project context before writing code.

Language Rules

1. Auto-detect input language → output in the same language
2. Japanese input → Japanese output, use references/code-guide.ja.md
3. English input → English output, use references/code-guide.md
4. Explicit override takes priority

Options

Execution Flow

Step 0: Context Loading (Phase A / Phase B)

Phase A — First invocation (full context):

1. Locate and read workflow (search order: docs/development/issue-to-pr-workflow.md → docs/ → find):
   • Identify your role as implementer
   • Read Agent definition file if referenced (e.g., .claude/agents/workflow-implementer.md)
2. Read Issue (if --issue provided):
   • Run gh issue view {N} --json title,body to understand the feature overview
3. Read all spec files in --spec directory:
   • requirement.md — what to build and why
   • design.md — how to build it (architecture, data models, interfaces)
   • tasks.md — all tasks and their relationships
   • Understand the full picture before focusing on your task
4. Read project rules (if they exist):
   • coding-rules.md (search: docs/development/ → docs/ → find)
   • CLAUDE.md / AGENTS.md at project root

Phase B — Feedback re-invocation (minimal context):

When called with --feedback, load only:

1. The feedback file (review or test results)
2. The target task description from tasks.md
3. The relevant design.md section
4. The changed files from the previous implementation

Do NOT re-read the full spec set unless the feedback indicates a misunderstanding of requirements.

Step 1: Locate Target Task

Parse tasks.md to find the task matching --task {task-id}:

• Extract: task name, requirements ID, design reference, target files, completion criteria
• If task is already checked [x], warn and stop

Step 2: Reference Design

Read the design section referenced by the task (e.g., "design.md §4.2"):

• Extract: architecture decisions, interfaces, data models
• Identify target files to create or modify

Step 3: Implement

Normal mode (no --feedback):

• Follow the design to implement the task
• Apply coding rules and project conventions
• Create or modify only the files specified in the task

Feedback mode (--feedback {file}):

The feedback file is auto-detected by its type: header line:

• type: review → Read ## Findings section. Fix only the findings tagged fix_before: implementation, at the specified file:line (Critical first, then Improvement). Findings tagged trial / required_check / follow_up are deferred — the caller carries them; do not fix them here. If no finding carries a fix_before tag (a legacy review file), fix Critical findings first, then Improvements.
• type: test → Read ## Test Cases for failures and ## Completion Criteria Coverage for uncovered criteria. Fix the failing tests by modifying implementation code.
• type: evaluate → Same ## Findings processing as type: review (identical ### Critical / ### Improvement structure). Fix Critical findings first, then Improvements. Ignore the ## Blocked section: blocked cases are setup gaps, not failures, and are not fix targets.

For both types:

• Focus on items marked as FAIL or - [ ] (unchecked)
• Do NOT modify code unrelated to the findings

Step 4: Verify Completion Criteria

Check each completion criterion from tasks.md:

• If criterion is met, note it
• If not met, continue implementing until satisfied
• Do NOT update the checkbox in tasks.md (this is spec-implement's responsibility)

Step 5: Commit

Commit the implementation following project conventions:

• Read commit message format from coding-rules.md or CLAUDE.md
• Default format: feat(scope): {task-id} — {brief description}
• Stage only implementation files (not tasks.md)

Error Handling

Usage Examples

# Implement a specific task
/spec-code --issue 36 --task T-007 --spec .specs/did-deactivation/

# Address review feedback
/spec-code --task T-007 --spec .specs/did-deactivation/ --feedback .specs/did-deactivation/review-T-007.md

# Address test failure feedback
/spec-code --task T-007 --spec .specs/did-deactivation/ --feedback .specs/did-deactivation/test-T-007.md

# Standalone (no issue)
/spec-code --task T-003 --spec .specs/auth-feature/