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 decompose-into-slicesgit 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/decompose-into-slices)<a href="https://agentmods.dev/skills/open-gsd/gsd-pi/decompose-into-slices"><img src="https://agentmods.dev/badge/skills/open-gsd/gsd-pi/decompose-into-slices/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/decompose-into-slices"><img src="https://agentmods.dev/badge/skills/open-gsd/gsd-pi/decompose-into-slices.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 | $0.00094 | $0.01808 |
| Opus 5 | $0.00047 | $0.00904 |
| Sonnet 5 | $0.00019 | $0.00362 |
| Haiku 4.5 | $0.00009 | $0.00181 |
Grade A, and why
decompose-into-slices 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 11d 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 — 140 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Typical invocation points:
- After
write-milestone-brief(or after adiscussphase that produced a brief) - When a roadmap exists but slices are too thick, too few, or poorly ordered
- When exporting the plan for external collaborators (GitHub issues)
<core_principle> VERTICAL, NOT HORIZONTAL. A slice that adds "schema + API + UI + tests for feature X on one narrow path" is vertical. A slice that adds "all schemas for all features" is horizontal and is wrong. Horizontal slices destroy the demoability property that makes slice completion meaningful.
MANY THIN, NOT FEW THICK. If a slice could be split into two demoable pieces, split it. Thin slices retire risk earlier, parallelize better, and give the user faster feedback on whether the direction is right.
DEPENDENCY GRAPH, NOT LINEAR LIST. Slices that don't depend on each other should be marked that way — depends:[] means the slice can start immediately. The GSD engine uses this to parallelize.
</core_principle>
Step 1: Load context
- Read
M###-CONTEXT.mdfor the active milestone — the brief is the source of truth for scope. - Read
M###-ROADMAP.mdif one exists — you may be refining rather than creating from scratch. - Read
src/resources/extensions/gsd/templates/roadmap.mdfor the exact slice format. The parser depends on it. - If the plan came from a GitHub issue (user passed a URL or number), fetch it with the active GitHub issue-read tool if one is available; use the exact tool name from the active tool list.
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.
- 11d ago First seen · 140 lines · 94 tokens per session scan A 461d8d256d0f
decompose-into-slices is a skill published in the GitHub repository open-gsd/gsd-pi (1,218 stars, last pushed today), licensed MIT. It adds 94 tokens to every session and 1,808 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-graphify
Build, query, and inspect the project knowledge graph in .planning/graphs/.
gsd-import
Ingest external plans with conflict detection against project decisions before writing anything.
gsd-mempalace-capture
File a phase artifact into MemPalace; mirror decision facts into its temporal KG.
gsd-mempalace-recall
Recall decisions, patterns, and surprises from MemPalace before planning.
gsd-quick
Execute a quick task with GSD guarantees (atomic commits, state tracking) but skip optional agents.
gsd-surface
Toggle which skills are surfaced — apply a profile, list, or disable a cluster without reinstall.