GSD Pi is a command-line coding agent and project workflow system that plans, implements, verifies, and tracks software work through milestones, tasks, Git worktrees, and stored project notes. It is for developers who want structured, longer-running agent sessions using different model providers. The catalogue entries extend GSD Pi with skills and agents.
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.
npx skills add open-gsd/gsd-pi --skill gsd-headlessgit clone --depth 1 https://github.com/open-gsd/gsd-piWrote 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/skills/open-gsd/gsd-pi/gsd-headless)<a href="https://agentmods.dev/skills/open-gsd/gsd-pi/gsd-headless"><img src="https://agentmods.dev/badge/skills/open-gsd/gsd-pi/gsd-headless/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/skills/open-gsd/gsd-pi/gsd-headless"><img src="https://agentmods.dev/badge/skills/open-gsd/gsd-pi/gsd-headless.svg" alt="Reviewed on agentmods" width="80" height="20"></a>- NVIDIA SkillSpector pass
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 | $0.00102 | $0.02415 |
| Opus 5 | $0.00051 | $0.01208 |
| Sonnet 5 | $0.00020 | $0.00483 |
| Haiku 4.5 | $0.00010 | $0.00242 |
Grade A, and why
gsd-headless 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 9d 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 — 247 lines — stays where its author put it; the contents beside it link to each section on GitHub.
GSD Headless Orchestration
Run GSD commands without TUI via gsd headless. Spawns an RPC child process, auto-responds to UI prompts, streams progress.
Command Syntax
gsd headless [flags] [command] [args...]
Flags:
--timeout N— overall timeout in ms;autohas no overall timeout unless this flag is set--json— JSONL event stream ending with the authoritativeheadless_result--model ID— override LLM model--thinking LEVEL— override thinking level (off,minimal,low,medium,high,xhigh,max)--resume <id>— resume a prior headless session by ID--bare— start with minimal context for CI/ecosystem use--verbose— show tool calls in progress output--supervised— forward interactive UI requests to orchestrator via stdout/stdin--response-timeout N— timeout for orchestrator response in supervised mode (default 30000)--max-restarts N— auto-restart on crash with backoff (default 3, 0 to disable)--answers <path>— pre-supply answers and secrets from JSON file--events <types>— filter JSONL output to specific event types (comma-separated, implies--json)
Exit codes: 0=complete, 1=error/timeout, 10=blocked, 11=cancelled
Core Workflows
1. Create + Execute a Milestone (end-to-end)
gsd headless new-milestone --context spec.md --auto
Reads spec, bootstraps .gsd/, creates milestone, then chains into auto-mode executing all phases (discuss → research → plan → execute → summarize → complete).
Extra flags for new-milestone: --context <path> (use - for stdin), --context-text <text>, --auto.
2. Run All Queued Work
gsd headless auto
Default command. Loops through all pending units until milestone complete or blocked.
3. Run One Unit
gsd headless next
Execute exactly one unit (task/slice/milestone step), then exit. Ideal for step-by-step orchestration with external decision logic between steps.
4. Instant State Snapshot (no LLM)
What ships with it
3 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.
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.
- 9d ago First seen · 247 lines · 102 tokens per session scan A 65696a0712ff
gsd-headless is a skill published in the GitHub repository open-gsd/gsd-pi (1,210 stars, last pushed today), licensed MIT. It adds 102 tokens to every session and 2,415 once invoked, about $0.0005 per session on Opus 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 2026-08-30.
Other skills, from other repositories
gsd-quick
Execute a quick task with GSD guarantees (atomic commits, state tracking) but skip optional agents.
gsd-complete-milestone
Archive completed milestone and prepare for next version.
gsd-quick-batch
Batch several /gsd:quick-shaped tasks together — planned, dispatched, and merged as one run.
gsd-workspace
Manage GSD workspaces — create, list, or remove isolated workspace environments.
gsd-inbox
Triage and review open GitHub issues and PRs against project templates and contribution guidelines.
gsd-pause-work
Create context handoff when pausing work mid-phase.