Getting it into your agent
It runs from inside its repository, so the clone comes first — what it calls does not travel with the file alone.
git clone --depth 1 https://github.com/emiliosheinz/agent-skillsnpx agentmods add skills/emiliosheinz/agent-skills/forgeWrote 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/emiliosheinz/agent-skills/forge)<a href="https://agentmods.dev/skills/emiliosheinz/agent-skills/forge"><img src="https://agentmods.dev/badge/skills/emiliosheinz/agent-skills/forge/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/emiliosheinz/agent-skills/forge"><img src="https://agentmods.dev/badge/skills/emiliosheinz/agent-skills/forge.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 | $0.00174 | $0.02734 |
| Opus 5 | $0.00087 | $0.01367 |
| Sonnet 5 | $0.00035 | $0.00547 |
| Haiku 4.5 | $0.00017 | $0.00273 |
Grade A, and why
forge 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 10d 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 — 215 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Forge
Forge runs spec-driven development as four phases. You invoke one phase at a time. Each
phase does its work, updates shared state, and recommends (but does not run) the next
phase. A fifth command, fix, re-enters the flow to correct course at any layer. Every
phase's depth auto-sizes to the change — see Sizing.
/forge specify <name> Understand the problem + capture requirements → spec.md
/forge design Architecture, contracts, verification gates → design.md
/forge plan Atomic tasks, dependencies, AC traces → plan.md
/forge execute Implement, then run independent verifiers → working code
/forge fix <change> Correct course mid-stream, keep the chain aligned → aligned artifacts + code
Dispatch
Read the first argument as the phase verb. Read the matching reference file fully before acting — it is the step-by-step playbook for that phase.
| Verb | Read | Produces |
|---|---|---|
specify |
references/specify.md (+ references/review.md) |
./.specs/<slug>/spec.md |
design |
references/design.md (+ references/review.md) |
./.specs/<slug>/design.md |
plan |
references/plan.md |
./.specs/<slug>/plan.md |
execute |
references/execute.md (+ references/verification.md) |
code + commits |
fix |
references/fix.md |
re-aligned artifacts + code |
If no verb is given, infer the phase from the request and confirm it. Never fail because a verb is missing or unknown. Common mappings:
| Request pattern | Phase |
|---|---|
| "write a PRD", "what should this do", problem with no proposed solution | specify |
| "design this", "how should we build X", architecture question | design |
| "break this into tasks", "plan the work" | plan |
| "implement X", "build this", spec + plan already exist | execute |
| "this detail is wrong", "correct course", "I don't like this design", "found a bug while testing", change to an in-flight spec/design/plan/code | fix |
What ships with it
15 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.
- README.md 4.7 KB
- references/design.md 6.1 KB
- references/execute.md 10 KB
- references/fix.md 7.3 KB
- references/lessons.md 4.0 KB
- references/plan.md 7.5 KB
- references/review.md 8.0 KB
- references/sizing.md 3.8 KB
- references/specify.md 13 KB
- references/verification.md 8.6 KB
- templates/design.md 1.5 KB
- templates/lessons.md 612 B
- templates/plan.md 1.5 KB
- templates/spec.md 3.5 KB
- templates/state.md 2.5 KB
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.
- 10d ago First seen · 215 lines · 174 tokens per session scan A 1b52393f8464
forge is a skill published in the GitHub repository emiliosheinz/agent-skills (18 stars, last pushed 1mo ago), licensed MIT. It adds 174 tokens to every session and 2,734 once invoked, about $0.0009 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.
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