GSD Core is a framework that guides AI coding agents through a repeatable cycle of discussing decisions, planning, executing, verifying, and shipping software work. It is used with coding-agent runtimes to organize research and implementation in fresh-context subagents and reduce context degradation. The catalogue entries are its skills, agents, hooks, plugin, and instructions for those workflows.
Getting it into your agent
One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.
git clone --depth 1 https://github.com/open-gsd/gsd-coreWrote this? Show the measurements
A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.
[](https://agentmods.dev/agents/open-gsd/gsd-core/gsd-roadmapper.compact)<a href="https://agentmods.dev/agents/open-gsd/gsd-core/gsd-roadmapper.compact"><img src="https://agentmods.dev/badge/agents/open-gsd/gsd-core/gsd-roadmapper.compact/github.svg" alt="Measured on agentmods" height="20"></a>Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.
<a href="https://agentmods.dev/agents/open-gsd/gsd-core/gsd-roadmapper.compact"><img src="https://agentmods.dev/badge/agents/open-gsd/gsd-core/gsd-roadmapper.compact.svg" alt="Reviewed on agentmods" width="80" height="20"></a>What it costs to keep this loaded
Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5.1 | $0.00036 | $0.04774 |
| Opus 5.5 | $0.00014 | $0.01910 |
| Sonnet 5.5 | $0.00007 | $0.00955 |
| Haiku 4.5 | $0.00004 | $0.00477 |
Grade A, and why
gsd-roadmapper scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 1mo ago.
A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.
Nothing flagged
None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.
How it starts
The opening of the file, as written. The whole thing — 455 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Spawned by /gsd:new-project orchestrator (unified project initialization).
Job: transform requirements into a phase structure that delivers the project. Every v1 requirement maps to exactly one phase. Every phase has observable success criteria.
CRITICAL: Mandatory Initial Read. If the prompt has a <required_reading> block, Read every listed file before anything else — primary context.
Context budget: load project skills first (lightweight); read implementation files incrementally, only what each check requires.
Project skills: check .claude/skills/ or .agents/skills/:
agent_skills: self-load per @~/.claude/gsd-core/references/agent-skills-bootstrap.md
- List available skills (subdirectories)
- Read
SKILL.mdper skill (lightweight index ~130 lines) - Load specific
rules/*.mdas needed - Do NOT load full
AGENTS.mdfiles (100KB+ context cost) - Ensure roadmap phases account for project skill constraints and implementation conventions.
Core responsibilities:
- Derive phases from requirements (not impose arbitrary structure)
- Validate 100% requirement coverage (no orphans)
- Apply goal-backward thinking at phase level
- Create success criteria (2-5 observable behaviors per phase)
- Initialize STATE.md (project memory)
- Write ROADMAP.md and STATE.md immediately (durability), then return a structured summary for the orchestrator to present; approval is the orchestrator's gate, revision is a re-run (#3797)
<downstream_consumer>
ROADMAP.md is consumed by /gsd:plan-phase:
| Output | How Plan-Phase Uses It |
|---|---|
| Phase goals | Decomposed into executable plans |
| Success criteria | Inform must_haves derivation |
| Requirement mappings | Ensure plans cover phase scope |
| Dependencies | Order plan execution |
Be specific. Success criteria must be observable user behaviors, not implementation tasks. </downstream_consumer>
Solo Developer + Claude Workflow
Roadmapping for ONE person (user) and ONE implementer (Claude). No teams, stakeholders, sprints, resource allocation. User is visionary/product owner; Claude is builder. Phases are buckets of work, not PM artifacts.
What this file has done since we first saw it
Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.
- 1mo ago First seen · 455 lines · 36 tokens per session scan A a48da45fc474
gsd-roadmapper is an agent published in the GitHub repository open-gsd/gsd-core (10,564 stars, last pushed today), licensed MIT. It adds 36 tokens to every session and 4,774 once invoked, about $0.0001 per session on Opus 5.5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-09-10.
Other agents, from other repositories
gsd-planner
Creates executable phase plans with task breakdown, dependency analysis, and goal-backward verification. Spawned by /gsd:plan-phase orchestrator.
gsd-executor
Executes GSD plans with atomic commits, deviation handling, checkpoint protocols, and state management. Spawned by execute-phase orchestrator or execute-plan command.
gsd-verifier
Verifies phase goal achievement through goal-backward analysis. Checks codebase delivers what phase promised, not just that tasks completed. Creates VERIFICATION.md report.
gsd-roadmapper
Creates project roadmaps with phase breakdown, requirement mapping, success criteria derivation, and coverage validation. Spawned by {{COMMANDPREFIX}}new-project orchestrator.
debugger
Hypothesis-driven bug investigation with root cause analysis.
scout
Fast codebase recon that returns compressed context for handoff to other agents.