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 agentmods add skills/kazdenc/builder-skills/specnpx skills add kazdenc/builder-skills --skill specgit clone --depth 1 https://github.com/kazdenc/builder-skillsWrote 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/kazdenc/builder-skills/spec)<a href="https://agentmods.dev/skills/kazdenc/builder-skills/spec"><img src="https://agentmods.dev/badge/skills/kazdenc/builder-skills/spec.svg" alt="Measured on agentmods" 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 | $0.00064 | $0.01094 |
| Opus 5 | $0.00032 | $0.00547 |
| Sonnet 5 | $0.00013 | $0.00219 |
| Haiku 4.5 | $0.00006 | $0.00109 |
Grade A, and why
spec 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 6d 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 — 133 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Technical Specification
A tech spec answers how we'll build something — without over-prescribing implementation details that engineers should own. It bridges product requirements to engineering execution.
Step 1: Read the Requirements
Before writing, gather the inputs. A spec without requirements is guesswork.
| Source | What to pull from it |
|---|---|
| PRD | Problem, goals, functional requirements, non-functional requirements, scope boundaries |
| Job stories | User workflows, acceptance criteria, edge cases |
| Conversation | If neither exists, interview the user to establish what the system must do and for whom |
Flag anything ambiguous. A spec built on vague requirements produces vague engineering.
Step 2: Write the Spec
Use this structure. Adapt headings to the project — not every section applies every time.
# Tech Spec: [Feature / System Name]
## Overview
One paragraph. What this is, why we're building it, and what it connects to.
Link to the PRD or source requirements.
## Technical Approach
The core design decision. How this fits into the existing system.
Keep it to the architecture level — components, their responsibilities,
how they interact. Don't write pseudocode unless it clarifies a tricky algorithm.
## Data Model
New tables, fields, or schema changes. Include:
- Field name, type, constraints
- Relationships to existing models
- Migration notes (new table vs altering existing)
## API Design
Endpoints, methods, request/response shapes.
For each endpoint:
- Method + path
- Request body / params
- Response shape
- Error cases
## Edge Cases
What happens when things go wrong or get weird.
| Case | Behavior | Rationale |
|------|----------|-----------|
| User submits duplicate | Return existing record, don't create new | Prevents data bloat |
| Payload exceeds size limit | Reject with 413, log for monitoring | Protects downstream services |
## Testing Strategy
What gets tested and how.
- Unit tests: which modules, what coverage target
- Integration tests: which workflows end-to-end
- Manual QA: what can't be automated and why
## Migration Plan
Only if changing existing systems. Cover:
- Data migration steps
- Backward compatibility (can old and new coexist during rollout?)
- Rollback procedure
## Rollout Plan
How this gets to users.
- Feature flag strategy
- Phased rollout stages (internal → beta → GA)
- Monitoring and alerting during rollout
- Success/failure criteria for each stage
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.
- 6d ago First seen · 133 lines · 64 tokens per session scan A 159fa9ca1d9f
spec is a skill published in the GitHub repository kazdenc/builder-skills (44 stars, last pushed 6mo ago), licensed MIT. It adds 64 tokens to every session and 1,094 once invoked, about $0.0003 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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