
SPECTRE
Joe Fernandez (Codename Inc) · Coding · Productivity
SPECTRE is a free, open-source agentic engineering workflow that plugs into Claude Code and Codex and turns a rough feature idea into reviewed, tested, shipped code. It runs the work through a slash command workflow that covers scoping, planning, execution, review, and cleanup. Think of it as spec-driven development for AI coding agents: you agree on the plan first, then the agent builds. You stay in the loop for the decisions that matter, and your coding agent handles the rest. It's built for developers who want consistent, repeatable results instead of one-off lucky prompts.

About SPECTRE
What Is SPECTRE
SPECTRE is a plugin-based AI coding agent workflow, not a standalone app you sign into. You install it into Claude Code or Codex, then start work by typing a single command. From there it walks your agent through a fixed sequence: scope the feature, write the technical design, break it into tasks, execute them with subagents, review the output, and open a pull request.
The problem it targets is ambiguity. When a request is vague, the model fills the gaps with guesses, and you end up with tangled code and rework. SPECTRE forces the missing detail into durable documents first. That's the core of its spec-driven development approach, so the agent builds from an agreed plan rather than an assumption. Joe Fernandez, the developer, built it after using it to ship his own products.
The catch is scope. SPECTRE is designed for standard-sized features inside a repo. For copy tweaks, styling passes, or giant multi-phase builds, the author points you elsewhere. It also assumes you already have Claude Code or Codex running and know your way around a terminal.
Getting Started
- Add the SPECTRE marketplace in Claude Code or Codex, then install the plugin.
- Restart or open a new session so the managed subagents get discovered.
- Run the scope command, such as
/spectre:spectre-scope, and answer its questions until the feature scope is settled. - Move through the plan and execute steps, reviewing the handoff before any code changes.
- Finish with ship, which cleans up the branch, runs tests, and opens the pull request.
Product Information
A quick look at SPECTRE's pricing, supported platforms, and performance.
Best for
The users, tasks, and scenarios where this tool fits best.
Users
- Developers already using Claude Code or Codex who want their agent to produce more consistent results on real features, and who don't mind a terminal workflow.
- Solo builders and indie hackers shipping product features without a team to catch mistakes, provided they'll follow the scope-and-plan steps instead of jumping straight to code.
- Technical product managers and ex-coders who write specs and want an agent to carry the plan through to a tested pull request.
Tasks
- Turning an unclear feature request into a written scope, a technical design, and a task list before any code gets written.
- Running parallel coding subagents that each get only the context their task needs.
- Cleaning up a branch by pruning dead code, adding tests, and preparing a pull request.
Scenarios
- Starting a brand new product where you have an idea but the exact feature boundaries aren't clear yet.
- Working through a highly technical question that needs codebase research before anyone writes a line.
- Picking a feature back up weeks later and letting a saved session handoff bring the agent back up to speed.
- Cleaning up a messy branch before a pull request. It handles the boring parts.
Key features
One Command to Start Building
Every piece of feature work enters through a single scope command. You don't memorize a sprawling menu of steps. Just one. So what does the slash command workflow actually do? The scope flow explores the edges of your idea and separates what's in, what's out, what's future, and what's explicitly anti-scope. For someone juggling several projects, that single entry point is the whole point.
Workflow Commands for the Full Lifecycle
SPECTRE ships as a set of slash commands, from /spectre:spectre-kickoff for hazy new features to /spectre:spectre-ship for final closeout. Plan, execute, prove, and handoff all live here too. The agent suggests the next command at the end of each response. So you rarely have to think about which one comes next.
Automatic Subagent Dispatch
SPECTRE routes specific jobs to specialized subagents: one to implement, one to analyze how existing code works, one to find reusable patterns, one to research the web, and one to review. The prompts call them for you, so you don't have to. That's a real time saver. Handing each subagent only the context its task needs keeps it focused. Less noise, fewer wrong turns.
Proof That the Feature Actually Works
Before you call a feature done, the prove step turns the scope and user flows into acceptance criteria and checks them through your test setup. It captures screenshots or video for visual work and builds a reviewable proof page. Anyone who's shipped a feature that "passed" but broke in the browser will see the value here.
Session Memory Across Context Windows
Run a handoff command when your context window fills up or you switch tasks. SPECTRE writes a status snapshot and loads it into your next session automatically, merging the last few snapshots into one continuous memory. That means you can clear the window without losing the thread. Nice. No more re-explaining the whole project to a fresh session.
Durable Knowledge That Compounds
SPECTRE captures verified gotchas, decisions, patterns, and blockers as structured records. A size-bounded startup index surfaces only the relevant ones for a given task. The agent then loads the full record after checking it still applies. Over time your project accumulates context. It doesn't reset to zero each session.
Parallel Task Execution With Review
Execute splits the plan into tasks, dispatches them to parallel subagents, and runs verification after each wave. Then it adds an opposite-runtime adversarial code review, followed by a repair pass. In plain terms, a different model checks the work. That catches blind spots a single agent tends to miss. It's not a guarantee. But it's a lot better than hoping.
Pros and cons
Pros
- Free and open source under the MIT license, so you can read every skill and prompt it runs.
- Works with both Claude Code and Codex, so you aren't tied to one coding agent.
- Forces clarity before code, which cuts the rework that vague prompts cause.
- Session handoffs and durable knowledge survive context resets and long gaps between sessions.
Cons
- Heavier than a plain prompt. For a one-line copy change, the back-and-forth is more ceremony than most people want.
- Needs an existing Claude Code or Codex setup and comfort with the terminal, so beginners are shut out.
- The author reports it's not built for massive multi-phase builds. You have to split those into phases yourself.
- It's a personal project maintained by one developer, so features and docs can shift without much notice.
Frequently asked questions
Yes. It's released under the MIT license and costs nothing to install or use. The only cost is whatever you already pay for Claude Code or Codex, since SPECTRE runs on top of those tools rather than replacing them.
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