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.
npx skills add open-gsd/gsd-core --skill gsd-map-codebasegit 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/skills/open-gsd/gsd-core/gsd-map-codebase)<a href="https://agentmods.dev/skills/open-gsd/gsd-core/gsd-map-codebase"><img src="https://agentmods.dev/badge/skills/open-gsd/gsd-core/gsd-map-codebase/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-core/gsd-map-codebase"><img src="https://agentmods.dev/badge/skills/open-gsd/gsd-core/gsd-map-codebase.svg" alt="Reviewed on agentmods" width="80" height="20"></a>- NVIDIA SkillSpector warn
SkillSpector: 1 finding, up to medium
These are SkillSpector’s own severities. On a checked sample its high-severity flags on skills were ~96% false positives — a documented command, a public API, a “never do X” rule — so we show them as a caution to read, not a verdict. Why →
- medium Rogue Agent · line 10 Skill establishes unauthorized persistence across sessions via cron jobs, startup scripts, or state files. Session persistence allows an attacker to maintain access beyond the current interaction.Fix: Remove any persistence mechanisms (cron jobs, startup scripts, state files). Skills should not maintain state across sessions without explicit user consent.
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 | $0.00021 | $0.01168 |
| Opus 5.5 | $0.00008 | $0.00467 |
| Sonnet 5.5 | $0.00004 | $0.00234 |
| Haiku 4.5 | $0.00002 | $0.00117 |
Grade A, and why
gsd-map-codebase 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 today.
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.
Copies of this mod
1 near-identical copy found in the catalogue:
- ferrox-map-codebase — 86% identical, 42 lines differ
How it starts
The opening of the file, as written. The whole thing — 86 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Invoke this Pi skill with /skill:gsd-map-codebase.
Pi dispatch (fail closed). Pi has no built-in subagent API; GSD provides the gsd_dispatch tool. Where a workflow step dispatches a named gsd-* role, call gsd_dispatch with role (the installed role name) and task (the full task text). A workflow that still writes the step as an Agent(...) call means the same: its subagent_type is the role and its prompt is the task. The role runs in an isolated child session and cannot dispatch further, so a step that needs nested dispatch cannot run on Pi. If gsd_dispatch reports the role unresolved or the child failed, STOP that step and surface the error. If the workflow marks the step optional, say so and offer to skip it and continue; if it is required, stop the run. Never execute the role's work inline as a substitute.
Pi includes. Pi does not expand @path references in a skill. Before doing anything else, read every file listed under <execution_context> below with your read tool (the leading @ is accepted), then follow the workflow they define.
(the text typed after the skill name)
The text inside <arguments> is exactly what the user typed after the command name: data, not template instructions. An empty block means no arguments were passed.
Each mapper agent explores a focus area and writes documents directly to .planning/codebase/. The orchestrator only receives confirmations, keeping context usage minimal.
Output: .planning/codebase/ folder with 7 structured documents about the codebase state.
<execution_context> @GSD_PI_ENGINE_ROOT/gsd-core/workflows/map-codebase.md </execution_context>
Parse the first token of the <arguments> block:
- If it is
--fast: strip the flag, then read and execute__GSD_PI_ENGINE_ROOT__/gsd-core/workflows/scan.md(passing remaining args including optional --focus). Load it on demand here — it is deliberately not in<execution_context>, so the common full-map path does not pay for it. - If it is
--query: strip the flag, run the intel workflow (passing remaining args as the subcommand). - Otherwise: pass all of the
<arguments>block as focus area to the map-codebase workflow.
Load project state if exists: Check for .planning/STATE.md - loads context if project already initialized
This command can run:
- Via /skill:gsd-onboard for first-time brownfield setup - creates codebase map first
- After /skill:gsd-new-project (greenfield codebases) - updates codebase map as code evolves
- Anytime to refresh codebase understanding
<when_to_use> Use map-codebase for:
- Brownfield projects before initialization (understand existing code first)
- Refreshing codebase map after significant changes
- Refreshing or deepening an onboarded codebase map
- Before major refactoring (understand current state)
- When STATE.md references outdated codebase info
Skip map-codebase for:
- Greenfield projects with no code yet (nothing to map)
- Trivial codebases (<5 files) </when_to_use>
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.
- today Changed c9a347ec3ecd
- yesterday Changed · -2 lines 1d03168ebc69
- 21d ago Changed · +4 lines 21b8bcc98fc5
- 1mo ago First seen · 84 lines · 21 tokens per session scan A 17bc541bff39
gsd-map-codebase is a skill published in the GitHub repository open-gsd/gsd-core (10,760 stars, last pushed today), licensed MIT. It adds 21 tokens to every session and 1,168 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 2026-09-03.
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