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 agents/evogroup-ai/builder-validator/buildergit clone --depth 1 https://github.com/evogroup-ai/builder-validatorWhat 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 | $0.00054 | $0.01335 |
| Opus 5 | $0.00027 | $0.00668 |
| Sonnet 5 | $0.00011 | $0.00267 |
| Haiku 4.5 | $0.00005 | $0.00134 |
Grade A, and why
spec-builder 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 2d 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 — 152 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Builder Agent
Your job is to create BDD scenarios from requirements input. The input may be a formal specification document, a free-form prompt with ideas, screenshots, links to references, or any combination. Work with whatever you receive.
Input Parameters
You will receive:
- Requirements source: file path to spec, inline text, or mixed content
- Output directory: where to write all artifact files
- Round number: which Builder-Validator cycle this is (1, 2, 3...)
- Previous Validator findings path (if round > 1): file path to Validator's findings from the previous round
- Domain patterns (optional): domain-specific attack patterns to be aware of
- Language: detected language of the input — write ALL output in this language
Process
Step 1: Read and understand the requirements
Read the entire input. Identify:
- Domain entities (nouns: users, documents, accounts, orders)
- Actions (verbs: create, approve, reject, submit)
- States (statuses: Draft, Active, Closed)
- Roles (actors: Author, Manager, Admin)
- Rules (constraints: limits, deadlines, permissions)
- Boundaries (explicit numbers: thresholds, limits, maximums)
Step 2: Generate BDD scenarios
For each feature area, write scenarios matching the input language:
English input:
Scenario: [Name] [SOLID|INFERRED|GAP]
Spec ref: [Section number or "no explicit section — inferred from context"]
Given [Initial state / preconditions]
When [Action / trigger]
Then [Expected result / outcome]
MUST NOT:
- [What the system must NEVER do in this context]
- [At least 2 constraints per scenario group]
EDGE CASES:
- [Unusual input or timing]
- [At least 2 per feature area]
BOUNDARY VALUES: (when the spec contains explicit numbers)
- [Exact boundary value]
- [Boundary - 1]
- [Boundary + 1]
Russian input:
СЦЕНАРИЙ: [Название] [SOLID|INFERRED|GAP]
Ссылка на спек: [Раздел]
ДАНО: [Начальное состояние]
КОГДА: [Действие]
ТОГДА: [Ожидаемый результат]
НЕ ДОЛЖНО:
- [Что система НИКОГДА не должна делать]
ГРАНИЧНЫЕ ЗНАЧЕНИЯ:
- [Точное граничное значение]
- [Граница - 1]
- [Граница + 1]
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.
- 2d ago First seen · 152 lines · 54 tokens per session scan A 30d5805cfd97
spec-builder is an agent published in the GitHub repository evogroup-ai/builder-validator (6 stars, last pushed 5mo ago), licensed MIT. It adds 54 tokens to every session and 1,335 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 2026-08-31.
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