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 NickPolyder/NP.CoPilot.Config --skill feature-design-docgit clone --depth 1 https://github.com/NickPolyder/NP.CoPilot.ConfigWrote 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/nickpolyder/np.copilot.config/feature-design-doc)<a href="https://agentmods.dev/skills/nickpolyder/np.copilot.config/feature-design-doc"><img src="https://agentmods.dev/badge/skills/nickpolyder/np.copilot.config/feature-design-doc/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/nickpolyder/np.copilot.config/feature-design-doc"><img src="https://agentmods.dev/badge/skills/nickpolyder/np.copilot.config/feature-design-doc.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 | $0.00043 | $0.00904 |
| Opus 5.5 | $0.00017 | $0.00362 |
| Sonnet 5.5 | $0.00009 | $0.00181 |
| Haiku 4.5 | $0.00004 | $0.00090 |
Grade A, and why
feature-design-doc 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.
How it starts
The opening of the file, as written. The whole thing — 107 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Purpose
Shared policy: Follow
instructions/coordination.instructions.mdfor precedence, invocation, delegation, and handoffs. Applyinstructions/workflow.instructions.mdfor proportional work and verification.
You are producing a design document that translates approved research and feature intent into a clear implementation blueprint.
Your goals are to:
- Clarify scope — ask only the key questions needed to resolve ambiguity.
- Document the design — create
design.mdwith the required sections and enough detail to implement. - Ground decisions — align with existing codebase patterns, abstractions, constraints, and project instructions.
- Prepare handoff — make the next atomic step,
task-breakdown, straightforward.
When to use this skill
Use this skill whenever:
- Codebase research is complete and the user approves moving to design.
- A feature needs a standalone
docs/features/{feature-name}/design.md. - The user asks for a feature design document grounded in an existing repository.
- You need the second atomic step in the chain:
codebase-research→feature-design-doc→task-breakdown→implementation-runner.
Do not use this skill for:
- Initial codebase investigation — use
codebase-research. - Generating implementation tasks — use
task-breakdown. - Executing code changes — use
implementation-runner. - Comprehensive plan-only orchestration — recommend
feature-planninginstead of nesting it.
Workflow
Produce a design document that a developer (including a junior) could implement from.
-
Ask 2-3 clarifying questions — scope, constraints, preferences. Keep questions informed by the research.
-
Generate
docs/features/{feature-name}/design.mdwith these sections:- Overview — what and why, in 2-3 sentences.
- Goals — measurable outcomes.
- User Stories — as a [role], I want [action], so that [value]. Include acceptance criteria.
- Scope — what's in, what's explicitly out.
- Data Model — entities, relationships, migrations needed.
- API Design — endpoints, request/response shapes, status codes.
- UI Design — components, layouts, user flows (if applicable).
- Test Strategy — planning summary of what to test at each pyramid level; recommend
test-strategyfor dedicated depth. - Security Considerations — planning summary of authentication, authorization, and input validation; recommend
security-auditfor STRIDE/OWASP depth. - Open Questions — anything unresolved.
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 · -11 lines 3165856f777a
- 1mo ago First seen · 118 lines · 43 tokens per session scan A 8910385de271
feature-design-doc is a skill published in the GitHub repository NickPolyder/NP.CoPilot.Config (2 stars, last pushed 1mo ago), licensed MIT. It adds 43 tokens to every session and 904 once invoked, about $0.0002 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 2026-08-31.
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