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/jasonkneen/kiro/spec-driven-developmentnpx skills add jasonkneen/kiro --skill spec-driven-developmentgit clone --depth 1 https://github.com/jasonkneen/kiroWrote 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/jasonkneen/kiro/spec-driven-development)<a href="https://agentmods.dev/skills/jasonkneen/kiro/spec-driven-development"><img src="https://agentmods.dev/badge/skills/jasonkneen/kiro/spec-driven-development.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 | $0.00046 | $0.01334 |
| Opus 5 | $0.00023 | $0.00667 |
| Sonnet 5 | $0.00009 | $0.00267 |
| Haiku 4.5 | $0.00005 | $0.00133 |
Grade A, and why
spec-driven-development 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 5d 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 — 191 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Spec-Driven Development
A comprehensive methodology for systematic software feature development that ensures quality, maintainability, and successful delivery through structured planning.
When to Use This Skill
Ideal scenarios:
- Complex features with multiple components, integrations, or user interactions
- High-stakes projects where rework costs are significant
- Team collaboration requiring shared understanding
- AI-assisted development where clear structure improves output quality
- Knowledge preservation for future maintainers
Less suitable:
- Simple bug fixes with obvious solutions
- Experimental prototypes for rapid iteration
- Time-critical hotfixes requiring immediate action
- Well-established patterns with minimal ambiguity
The Three-Phase Workflow
Phase 1: Requirements Gathering
Purpose: Transform vague feature ideas into clear, testable requirements
Process:
- Capture user stories expressing value and purpose
- Define acceptance criteria using EARS format (Easy Approach to Requirements Syntax)
- Identify edge cases and constraints
- Validate completeness and feasibility
EARS Format Patterns:
WHEN [event] THEN [system] SHALL [response]
IF [precondition] THEN [system] SHALL [response]
WHEN [event] AND [condition] THEN [system] SHALL [response]
Example:
**User Story:** As a new user, I want to create an account, so that I can access personalized features.
**Acceptance Criteria:**
1. WHEN user provides valid email and password THEN system SHALL create new account
2. WHEN user provides existing email THEN system SHALL display "email already registered" error
3. WHEN user provides password shorter than 8 characters THEN system SHALL display "password too short" error
4. WHEN account creation succeeds THEN system SHALL send confirmation email
Phase 2: Design Documentation
Purpose: Create a comprehensive technical plan for implementation
Process:
- Research technical approaches and constraints
- Define system architecture and component interactions
- Specify data models and interfaces
- Plan error handling and testing strategies
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.
- 5d ago First seen · 191 lines · 46 tokens per session scan A e582197ad5da
spec-driven-development is a skill published in the GitHub repository jasonkneen/kiro (745 stars, last pushed 7mo ago), licensed MIT. It adds 46 tokens to every session and 1,334 once invoked, about $0.0002 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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