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speckit-plan

dceoy/speckit-agent-skills

Execute implementation planning workflows to generate design artifacts from feature specifications.

What is speckit-plan?

Speckit-plan is a workflow skill that guides you through structured implementation planning using templates. It reads your feature specification, executes a multi-phase design process (research, data modeling, contract definition), and generates design artifacts in your spec-kit project. Use this when you need to plan a feature before coding.

  • Validates spec-kit project structure and loads feature specifications
  • Executes pre-execution extension hooks if configured in .specify/extensions.yml
  • Generates research.md by resolving unknowns and documenting technology decisions
  • Creates data-model.md with entities, fields, relationships, and validation rules
  • Defines interface contracts for external-facing APIs, CLIs, or services
  • Produces quickstart.md with runnable validation scenarios

How to install speckit-plan

npx skills add https://github.com/dceoy/speckit-agent-skills --skill speckit-plan
Prerequisites
  • Spec-kit project with .specify/ directory structure
  • Feature specification file (FEATURE_SPEC) already created
  • Optional: .specify/extensions.yml for custom pre/post-execution hooks
Claude Code
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Cline

How to use speckit-plan

  1. 1.Run the skill with optional guidance for the planning phase as an argument
  2. 2.The skill will check for and execute any pre-plan hooks from .specify/extensions.yml
  3. 3.Review the generated research.md with resolved unknowns and technology decisions
  4. 4.Examine the data-model.md for entities and validation rules
  5. 5.Check the contracts/ directory for interface definitions (if applicable)
  6. 6.Review quickstart.md for end-to-end validation scenarios
  7. 7.Post-execution hooks will run automatically before completion

Use cases

Good for
  • Planning a new feature by researching unknowns and documenting design decisions before implementation
  • Generating data models and API contracts for a feature to align team understanding
  • Creating validation guides that prove a feature works end-to-end
  • Organizing design artifacts in a spec-kit project structure for downstream implementation tasks
Who it's for
  • Developers using spec-kit project structure
  • Teams planning features with formal design documentation
  • Projects requiring pre-implementation research and contract definition

speckit-plan FAQ

What is the difference between this skill and just writing a design doc?

Speckit-plan enforces a structured workflow with specific phases (research, design, contracts) and integrates with your spec-kit project's constitution and extension hooks, ensuring consistency and traceability across your feature planning.

Do I need to provide all the information upfront?

No. The skill identifies unknowns as 'NEEDS CLARIFICATION' in the Technical Context phase, then Phase 0 researches and resolves them before proceeding to design.

What if my project doesn't have external interfaces?

The contracts/ generation step is skipped for purely internal projects (build scripts, one-off tools). The skill will still generate data-model.md and quickstart.md.

Can I customize the planning workflow?

Yes. You can register pre-plan and after-plan hooks in .specify/extensions.yml to inject custom steps or validations before and after the workflow.

What happens if .specify/extensions.yml has invalid YAML?

The skill will report the parser error and tell you that no hooks were checked, then continue with the normal planning workflow.

Full instructions (SKILL.md)

Source of truth, from dceoy/speckit-agent-skills.


name: "speckit-plan" description: "Execute the implementation planning workflow using the plan template to generate design artifacts." argument-hint: "Optional guidance for the planning phase" compatibility: "Requires spec-kit project structure with .specify/ directory" metadata: author: "github-spec-kit" source: "templates/commands/plan.md" user-invocable: true disable-model-invocation: false

User Input

$ARGUMENTS

You MUST consider the user input before proceeding (if not empty).

Pre-Execution Checks

Check for extension hooks (before planning):

  • Check if .specify/extensions.yml exists in the project root.
  • If it exists, read it and look for entries under the hooks.before_plan key
  • If the YAML cannot be parsed or is invalid, do not skip silently: tell the user that .specify/extensions.yml could not be read (include the parser error) and that no hooks were checked, including any mandatory (optional: false) hooks registered there, then continue normally
  • Filter out hooks where enabled is explicitly false. Treat hooks without an enabled field as enabled by default.
  • For each remaining hook, do not attempt to interpret or evaluate hook condition expressions:
    • If the hook has no condition field, or it is null/empty, treat the hook as executable
    • If the hook defines a non-empty condition, skip the hook and leave condition evaluation to the HookExecutor implementation
  • When constructing command invocations from hook command names, replace dots (.) with hyphens (-). For example, speckit.git.commit → /speckit-git-commit.
  • For each executable hook, output the following based on its optional flag:
    • Optional hook (optional: true):

      ## Extension Hooks
      
      **Optional Pre-Hook**: {extension}
      Command: `/{command}`
      Description: {description}
      
      Prompt: {prompt}
      To execute: `/{command}`
      
    • Mandatory hook (optional: false):

      ## Extension Hooks
      
      **Automatic Pre-Hook**: {extension}
      Executing: `/{command}`
      EXECUTE_COMMAND: {command}
      
      Wait for the result of the hook command before proceeding to the Outline.
      

      After emitting the block above you MUST actually invoke the hook and wait for it to finish before continuing. Run it the same way you would run the command yourself in this agent/session (the invocation may differ from the literal {command} id shown above, e.g. a skills-mode agent runs it as /skill:speckit-... or $speckit-...). Emitting the block alone does not run the hook.

  • If no hooks are registered or .specify/extensions.yml does not exist, skip silently

Outline

  1. Setup: Run .specify/scripts/bash/setup-plan.sh --json from repo root and parse JSON for FEATURE_SPEC, IMPL_PLAN, FEATURE_DIR, BRANCH. For single quotes in args like "I'm Groot", use escape syntax: e.g 'I'''m Groot' (or double-quote if possible: "I'm Groot").

  2. Load context: Read FEATURE_SPEC and .specify/memory/constitution.md. Load IMPL_PLAN template (already copied).

  3. Execute plan workflow: Follow the structure in IMPL_PLAN template to:

    • Fill Technical Context (mark unknowns as "NEEDS CLARIFICATION")
    • Fill Constitution Check section from constitution
    • Evaluate gates (ERROR if violations unjustified)
    • Phase 0: Generate research.md (resolve all NEEDS CLARIFICATION)
    • Phase 1: Generate data-model.md, contracts/, quickstart.md
    • Re-evaluate Constitution Check post-design

Mandatory Post-Execution Hooks

You MUST complete this section before reporting completion to the user.

Check if .specify/extensions.yml exists in the project root.

  • If it does not exist, or no hooks are registered under hooks.after_plan, skip to the Completion Report.
  • If it exists, read it and look for entries under the hooks.after_plan key.
  • If the YAML cannot be parsed or is invalid, do not skip silently: tell the user that .specify/extensions.yml could not be read (include the parser error) and that no hooks were checked, including any mandatory (optional: false) hooks registered there, then continue to the Completion Report.
  • Filter out hooks where enabled is explicitly false. Treat hooks without an enabled field as enabled by default.
  • For each remaining hook, do not attempt to interpret or evaluate hook condition expressions:
    • If the hook has no condition field, or it is null/empty, treat the hook as executable
    • If the hook defines a non-empty condition, skip the hook and leave condition evaluation to the HookExecutor implementation
  • When constructing command invocations from hook command names, replace dots (.) with hyphens (-). For example, speckit.git.commit → /speckit-git-commit.
  • For each executable hook, output the following based on its optional flag:
    • Mandatory hook (optional: false) — You MUST emit EXECUTE_COMMAND: for each mandatory hook:

      ## Extension Hooks
      
      **Automatic Hook**: {extension}
      Executing: `/{command}`
      EXECUTE_COMMAND: {command}
      

      After emitting the block above you MUST actually invoke the hook and wait for it to finish before continuing. Run it the same way you would run the command yourself in this agent/session (the invocation may differ from the literal {command} id shown above, e.g. a skills-mode agent runs it as /skill:speckit-... or $speckit-...). Emitting the block alone does not run the hook.

    • Optional hook (optional: true):

      ## Extension Hooks
      
      **Optional Hook**: {extension}
      Command: `/{command}`
      Description: {description}
      
      Prompt: {prompt}
      To execute: `/{command}`
      

Completion Report

Command ends after Phase 1 design. Report branch, IMPL_PLAN path, and generated artifacts.

Phases

Phase 0: Outline & Research

  1. Extract unknowns from Technical Context above:

    • For each NEEDS CLARIFICATION → research task
    • For each dependency → best practices task
    • For each integration → patterns task
  2. Generate and dispatch research agents:

    For each unknown in Technical Context:
      Task: "Research {unknown} for {feature context}"
    For each technology choice:
      Task: "Find best practices for {tech} in {domain}"
    
  3. Consolidate findings in research.md using format:

    • Decision: [what was chosen]
    • Rationale: [why chosen]
    • Alternatives considered: [what else evaluated]

Output: research.md with all NEEDS CLARIFICATION resolved

Phase 1: Design & Contracts

Prerequisites: research.md complete

  1. Extract entities from feature spec → data-model.md:

    • Entity name, fields, relationships
    • Validation rules from requirements
    • State transitions if applicable
  2. Define interface contracts (if project has external interfaces) → /contracts/:

    • Identify what interfaces the project exposes to users or other systems
    • Document the contract format appropriate for the project type
    • Examples: public APIs for libraries, command schemas for CLI tools, endpoints for web services, grammars for parsers, UI contracts for applications
    • Skip if project is purely internal (build scripts, one-off tools, etc.)
  3. Create quickstart validation guide → quickstart.md:

    • Document runnable validation scenarios that prove the feature works end-to-end
    • Include prerequisites, setup commands, test/run commands, and expected outcomes
    • Use links or references to contracts and data model details instead of duplicating them
    • Do not include full implementation code, model/service/controller bodies, migrations, or complete test suites
    • Keep this artifact as a validation/run guide; implementation details belong in tasks.md and the implementation phase

Output: data-model.md, /contracts/*, quickstart.md

Key rules

  • Use absolute paths for filesystem operations; use project-relative paths for references in documentation
  • ERROR on gate failures or unresolved clarifications

Done When

  • Plan workflow executed and design artifacts generated
  • Extension hooks dispatched or skipped according to the rules in Mandatory Post-Execution Hooks above
  • Completion reported to user with branch, plan path, and generated artifacts