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 plainlang/plain-forge --skill add-implementation-requirementgit clone --depth 1 https://github.com/plainlang/plain-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/plainlang/plain-forge/add-implementation-requirement)<a href="https://agentmods.dev/skills/plainlang/plain-forge/add-implementation-requirement"><img src="https://agentmods.dev/badge/skills/plainlang/plain-forge/add-implementation-requirement/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/plainlang/plain-forge/add-implementation-requirement"><img src="https://agentmods.dev/badge/skills/plainlang/plain-forge/add-implementation-requirement.svg" alt="Reviewed on agentmods" width="80" height="20"></a>- NVIDIA SkillSpector pass
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 | $0.00065 | $0.00981 |
| Opus 5.5 | $0.00026 | $0.00392 |
| Sonnet 5.5 | $0.00013 | $0.00196 |
| Haiku 4.5 | $0.00006 | $0.00098 |
Grade A, and why
add-implementation-requirement 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 — 88 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Add Implementation Requirement
Always use the skill load-plain-reference to retrieve the ***plain syntax rules — but only if you haven't done so yet.
Workflow
- Identify the target
.plainfile. If ambiguous, ask the user. - Read the file to understand existing implementation reqs, definitions, and functional specs.
- Determine if this belongs in implementation reqs — it must describe HOW to build, not WHAT to build (that goes in
***functional specs***). - Draft the requirement following the rules below.
- Insert it into the
***implementation reqs***section. - Read the file again to confirm correct placement and syntax.
What Belongs Here
Implementation reqs are free-form instructions that steer code generation. Common contents:
- Technology choices: language, framework, runtime version
- Architectural constraints: patterns, layering, dependency rules
- Coding standards: naming conventions, style guidelines
- Data formats: serialization, encoding, transformation rules
- Error handling: strategies, retry logic, exception hierarchies
- Algorithm descriptions: specific approaches when behavior alone is insufficient
- Performance guidance: memory constraints, streaming requirements, batching strategies
- Language-specific constructs: generics, annotations, framework-specific types and idioms
What Does NOT Belong Here
- Behavior and features — those go in
***functional specs*** - Concept definitions — those go in
***definitions*** - Conformance-test instructions — those go in
***test reqs***. Note: unit-test instructions belong HERE, not in***test reqs***— see Unit-test guidance belongs here below
Unit-test guidance belongs here
Everything about :UnitTests: goes in ***implementation reqs*** — paths, approach, packages, framework (JUnit / pytest / Jest / Go's testing / …), conventions, fixtures, mocking policy, file layout, naming, lint / static-analysis gates. Unit tests are part of the generated codebase, so requirements that shape them are implementation reqs by definition.
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 First seen · 88 lines · 65 tokens per session scan A d7c4107bbd63
add-implementation-requirement is a skill published in the GitHub repository plainlang/plain-forge (79 stars, last pushed yesterday), licensed MIT. It adds 65 tokens to every session and 981 once invoked, about $0.0003 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 2026-08-30.
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