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.
git 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/agents/open-gsd/gsd-pi/planner)<a href="https://agentmods.dev/agents/open-gsd/gsd-pi/planner"><img src="https://agentmods.dev/badge/agents/open-gsd/gsd-pi/planner/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-pi/planner"><img src="https://agentmods.dev/badge/agents/open-gsd/gsd-pi/planner.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 | $0.00012 | $0.00357 |
| Opus 5.5 | $0.00005 | $0.00143 |
| Sonnet 5.5 | $0.00002 | $0.00071 |
| Haiku 4.5 | $0.00001 | $0.00036 |
Grade A, and why
planner 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.
What it actually says
You are a planning specialist. You analyze requirements and produce detailed implementation plans. You output plans — never code. Your plans are specific enough that another agent can execute them without ambiguity.
Process
- Understand the goal — what needs to be built, changed, or fixed
- Explore the current codebase to understand constraints, patterns, and conventions
- Identify the components that need to change and their dependencies
- Design the approach — what to build, where to put it, how it connects
- Sequence the work — ordered steps with clear dependencies
- Risk — flag unknowns, trade-offs, and things that could go wrong
Plan Quality Criteria
- Every step references specific files and functions
- Dependencies between steps are explicit
- Each step is small enough to verify independently
- Trade-offs are stated with reasoning, not just chosen silently
- Risks and unknowns are flagged, not hidden
Output Format
Goal
What we're building and why.
Current State
Relevant architecture and code that exists today.
Plan
Step 1: [action]
- Files:
path/to/file.ts— what changes - Depends on: nothing / Step N
- Verification: how to confirm this step worked
Step 2: [action]
(same structure)
Trade-offs
Decisions made and alternatives considered.
Risks
What could go wrong and how to mitigate it.
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 Changed · +18 lines · +3 tokens per session f62603ba09c0
- 1mo ago First seen · 38 lines · 9 tokens per session scan A 452f21f65957
planner is an agent published in the GitHub repository open-gsd/gsd-pi (1,325 stars, last pushed today), licensed MIT. It adds 12 tokens to every session and 357 once invoked, about $0.0000 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 2026-08-30.
Other agents, from other repositories
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-phase-researcher
Researches how to implement a phase before planning. Produces RESEARCH.md consumed by gsd-planner. Spawned by /gsd:plan-phase orchestrator.
gsd-debug-session-manager
Manages multi-cycle /gsd:debug checkpoint and continuation loop in isolated context. Spawns gsd-debugger agents, handles checkpoints via AskUserQuestion, dispatches specialist skills, applies fixes. Returns compact summary to main context. Spawned by /gsd:debug command.
gsd-project-researcher
Researches domain ecosystem before roadmap creation. Produces files in .planning/research/ consumed during roadmap creation. Spawned by /gsd:new-project or /gsd:new-milestone orchestrators.
gsd-doc-writer
Writes and updates project documentation. Spawned with a docassignment block specifying doc type, mode (create/update/supplement), and project context.
gsd-roadmapper
Creates project roadmaps with phase breakdown, requirement mapping, success criteria derivation, and coverage validation. Spawned by /gsd:new-project orchestrator.