[Extension]: Add TDD Extension

[d0whc3r]

Extension ID

tdd

Extension Name

TDD Extension

Version

1.1.2

Description

Drives spec-kit implementation with tests: a language-agnostic red-green-refactor loop with a per-feature test list, recorded red and green evidence, and mutation-checked test strength.

Author

d0whc3r

Repository URL

https://github.com/d0whc3r/spec-kit-tdd

Download URL

https://github.com/d0whc3r/spec-kit-tdd/releases/download/v1.1.2/tdd-1.1.2.zip

License

MIT

Homepage (optional)

https://d0whc3r.github.io/spec-kit-tdd/

Documentation URL (optional)

https://github.com/d0whc3r/spec-kit-tdd/wiki

Changelog URL (optional)

https://github.com/d0whc3r/spec-kit-tdd/blob/main/CHANGELOG.md

Required Spec Kit Version

=0.11.9

Required Tools (optional)

None. This extension is plain Markdown command and template text. It adds no external tool or runtime dependencies beyond Spec Kit itself.

Number of Commands

4

Number of Hooks (optional)

3

Tags

acceptance-tests, mutation-testing, property-based-testing, quality, red-green-refactor, spec-kit, spec-kit-extension, tdd, test-driven-development, test-first, testing, unit-tests

Key Features

• /speckit.tdd.setup: Detect the repository's test stack and write .specify/memory/tdd-profile.md with the exact verified commands the loop needs (single test, full suite, coverage, mutation), plus the TDD principle to add to the project constitution
• /speckit.tdd.plan: Derive the feature's test list from spec.md and plan.md into specs//tdd/test-list.md (outer acceptance behaviors, inner unit behaviors, each traced to an acceptance criterion) and make the test tasks in tasks.md mandatory and correctly ordered
• /speckit.tdd.run: Drive the red-green-refactor loop one behavior at a time from the test list: write one failing test, prove it fails for the right reason, make it pass with the smallest change, refactor while green, record the evidence in the feature's tdd/cycle-log.md, and tick the tasks.md tasks the completed behaviors cover
• /speckit.tdd.verify: Audit the feature's TDD discipline and test strength from cold context: test-first evidence in git history, red-phase evidence, test-smell rubric, mutation testing on the changed files, and acceptance-criteria coverage, then write specs//tdd/verification.md with a verdict and remediation tasks

Testing Checklist

• Extension installs successfully via download URL
• All commands execute without errors
• Documentation is complete and accurate
• No security vulnerabilities identified
• Tested on at least one real project

Submission Requirements

• Valid extension.yml manifest included
• README.md with installation and usage instructions
• LICENSE file included
• GitHub release created with version tag
• All command files exist and are properly formatted
• Extension ID follows naming conventions (lowercase-with-hyphens)

Testing Details

Tested by the https://github.com/d0whc3r/spec-kit-tdd release pipeline (release):

• Manifest validation (pnpm run validate) confirms extension.yml and catalog.json agree on version, command count, and hook count.
• Content lint (pnpm run lint:content) enforces the output style rules every command must follow.
• The release archive tdd-1.1.2.zip is built and attached to the GitHub release at tag v1.1.2.
• Install is exercised from the published download URL above.

Test project: the committed examples/ artifacts (a test list, a cycle log, and a verification report) come from running the full loop on a real codebase.

Example Usage

# Install the extension from the release archive
specify extension add tdd --from https://github.com/d0whc3r/spec-kit-tdd/releases/download/v1.1.2/tdd-1.1.2.zip

# Once per repository: detect and verify the test stack
/speckit.tdd.setup

# Per feature, after /speckit.tasks: derive the test list
/speckit.tdd.plan

# Drive the red-green-refactor loop, one behavior per cycle
/speckit.tdd.run
/speckit.tdd.run all

# Audit the discipline and the strength of the tests from cold context
/speckit.tdd.verify

Proposed Catalog Entry

{
  "tdd": {
    "name": "TDD Extension",
    "id": "tdd",
    "description": "Drives spec-kit implementation with tests: a language-agnostic red-green-refactor loop with a per-feature test list, recorded red and green evidence, and mutation-checked test strength.",
    "author": "d0whc3r",
    "version": "1.1.2",
    "download_url": "https://github.com/d0whc3r/spec-kit-tdd/releases/download/v1.1.2/tdd-1.1.2.zip",
    "repository": "https://github.com/d0whc3r/spec-kit-tdd",
    "homepage": "https://d0whc3r.github.io/spec-kit-tdd/",
    "documentation": "https://github.com/d0whc3r/spec-kit-tdd/wiki",
    "changelog": "https://github.com/d0whc3r/spec-kit-tdd/blob/main/CHANGELOG.md",
    "license": "MIT",
    "category": "process",
    "effect": "read-write",
    "requires": {
      "speckit_version": ">=0.11.9"
    },
    "provides": {
      "commands": 4,
      "hooks": 3
    },
    "tags": [
      "acceptance-tests",
      "mutation-testing",
      "property-based-testing",
      "quality",
      "red-green-refactor",
      "spec-kit",
      "spec-kit-extension",
      "tdd",
      "test-driven-development",
      "test-first",
      "testing",
      "unit-tests"
    ],
    "created_at": "2026-08-03T00:00:00Z",
    "updated_at": "2026-08-03T19:26:51Z"
  }
}

Additional Context

Full user documentation lives on the project website (https://d0whc3r.github.io/spec-kit-tdd/) and the project wiki, with reference docs at https://github.com/d0whc3r/spec-kit-tdd/wiki. Source repository: https://github.com/d0whc3r/spec-kit-tdd.

A complete, real worked example (a test list, the cycle log with its recorded red output, and the verification report) is committed at https://github.com/d0whc3r/spec-kit-tdd/tree/main/examples so reviewers and users can see exactly what each command reads and writes.

[github-actions]

cc @github/spec-kit-maintainers — new catalog submission for review.

[github-actions]

Pull request created: #3982

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