opsx-feature-dev

A Claude Code plugin that combines systematic feature development (codebase exploration, architecture design, quality review) with OpenSpec artifact-driven documentation.

What It Does

Instead of jumping straight into code, this plugin guides you through a 7-phase workflow where every decision, design, and task is captured in OpenSpec artifacts - making the work traceable, resumable, and reviewable.

The 7 Phases

Phase	Goal	Produces
1. Discovery	Understand what to build	OpenSpec change created
2. Codebase Exploration	Understand existing code	Findings summary via code-explorer agents
3. Clarifying Questions	Resolve all ambiguities	User answers
4. Architecture & Artifacts	Design and document	proposal.md, design.md, tasks.md
5. Implementation	Build the feature	Code changes, task checkboxes
6. Quality Review	Verify quality	Review findings via code-reviewer agents
7. Summary & Archive	Document completion	Summary, optional archive

Specialized Agents

• code-explorer - Traces execution paths, maps architecture layers, documents dependencies
• code-architect - Designs architectures with implementation blueprints, analyzes codebase patterns
• code-reviewer - Reviews for bugs, quality issues, and project convention adherence (confidence >= 80 threshold)

Prerequisites

• Claude Code installed
• OpenSpec CLI installed and configured in your project
• OpenSpec skills installed in your project (these are managed by the openspec CLI)

Installation

First, add the repo as a marketplace source:

claude plugin marketplace add mbertani/opsx-feature-dev

Then install the plugin:

claude plugin install opsx-feature-dev

Usage

# Full workflow with description
/opsx-feature-dev:feature-dev Add rate limiting to API endpoints

# Or start interactively
/opsx-feature-dev:feature-dev

The command guides you through each phase, waiting for your input at key decision points (clarifying questions, architecture choice, implementation approval).

When to Use This

• New features touching multiple files
• Features requiring architectural decisions
• Complex integrations with existing code
• Features where requirements are unclear

When NOT to Use This

• Single-line bug fixes
• Trivial, well-defined changes
• Urgent hotfixes

How It Integrates with OpenSpec

This plugin layers on top of the core openspec skills rather than bundling them. The openspec CLI manages its own skills (explore, propose, apply, archive) and generates them to match the CLI version. This plugin adds the feature-dev workflow that calls the openspec CLI directly and references the opsx skills by name.

The workflow creates an OpenSpec change in Phase 1 and uses openspec instructions to generate properly structured artifacts. The implementation phase works through tasks.md exactly like /opsx:apply. When done, you can archive with /opsx:archive.

This means you can:

• Pause mid-workflow and resume later with /opsx:apply
• Review artifacts independently of the workflow
• Archive completed work with full traceability

Keeping in Sync

This plugin has two upstream dependencies that may change independently:

1. OpenSpec CLI — the openspec commands and artifact structure
2. Official feature-dev plugin — the agent prompts (code-explorer, code-architect, code-reviewer)

Syncing with the official feature-dev plugin

The three agent files (code-explorer, code-architect, code-reviewer) are derived from Anthropic's feature-dev plugin. The UPSTREAM_VERSION file tracks which version they were last synced from.

When Anthropic updates the official plugin:

# 1. Pull the latest official plugin into your local cache
claude plugin update feature-dev

# 2. Compare your agents against the new version
./update-from-upstream.sh

# 3. If agent diffs are shown, apply them automatically
./update-from-upstream.sh --apply

# 4. Review and commit
git diff
git commit -am "Sync agents with upstream"
git push

The script will:

• Show whether a new upstream version is available (hash comparison)
• Diff each agent file and the command file
• With --apply: copy updated agents and update the UPSTREAM_VERSION hash

The command file (feature-dev.md) will always differ from upstream because it includes the OpenSpec integration. The script flags this but won't overwrite it - review command diffs manually for workflow changes you may want to incorporate.

Syncing with OpenSpec CLI

Run the compatibility check to verify the openspec CLI commands this plugin uses still work:

./check-compat.sh

This compares your installed openspec CLI version against the version recorded in OPENSPEC_COMPAT and verifies all required CLI commands are available.

OpenSpec CLI commands used by this plugin

• openspec new change "<name>" — creates a change directory
• openspec status --change "<name>" --json — reads artifact graph and schema
• openspec instructions <artifact-id> --change "<name>" --json — gets artifact templates/rules
• openspec instructions apply --change "<name>" --json — gets implementation context
• openspec list --json — lists active changes

If any of these change their JSON output shape or flags, the feature-dev.md command may need updating.

After an openspec CLI upgrade

1. Run ./check-compat.sh to see if anything changed
2. If the script reports issues, check the openspec changelog
3. Update commands/feature-dev.md if CLI flags or JSON output changed
4. Update OPENSPEC_COMPAT with the new tested version

Related Skills

The openspec CLI provides these skills (managed separately):

• /opsx:explore - Thinking partner for exploration
• /opsx:propose - Quick artifact generation without the full workflow
• /opsx:apply - Implement tasks from an existing change
• /opsx:archive - Archive completed changes

License

MIT