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/plainlang/plain-forge/add-functional-specsnpx skills add plainlang/plain-forge --skill add-functional-specsgit clone --depth 1 https://github.com/plainlang/plain-forgeWhat 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 | $0.00097 | $0.01999 |
| Opus 5 | $0.00048 | $0.01000 |
| Sonnet 5 | $0.00019 | $0.00400 |
| Haiku 4.5 | $0.00010 | $0.00200 |
Grade A, and why
add-functional-specs 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 — 120 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Add Functional Specs
Always use the skill load-plain-reference to retrieve the ***plain syntax rules — but only if you haven't done so yet.
When to Use
- The user asks for several functional specs to be added in one go (e.g. "add these three specs", "spec out this feature in a few bullets").
- A higher-level skill or workflow (
forge-plain,add-feature,debug-specs) needs to author a tight group of related specs. - Anywhere you would otherwise be tempted to write more than one functional spec without running per-spec analysis.
If you only need to add a single spec, use the add-functional-spec skill instead. Either way, never edit the ***functional specs*** section by hand — every new entry must go through one of these two skills so the complexity and conflict checks actually run.
Workflow
This skill is add-functional-spec applied one spec at a time, in order, with no shortcuts. The batch never escapes per-spec rigor.
- Identify the target
.plainfile. If ambiguous, ask the user. - Read the entire file to understand existing definitions, implementation reqs, and all current functional specs (including those reachable via
import/requires). - Draft all the specs you intend to add, in the chronological order they should appear. Keep the drafts in a working list — nothing is inserted yet. Run the review pass in
concise-specs.mdover every draft before continuing; trim each to the shortest wording that keeps every fact. - For each drafted spec, in order:
- Analyze complexity. Run
analyze-if-func-spec-too-complexon the spec. If the verdict isTOO COMPLEX, runbreak-down-func-spec, replace the entry in the working list with the resulting smaller specs (preserving order), and restart this step on the first of the replacements. - Check for conflicts. Run
analyze-func-specsonce with this single input set:- the new spec, plus
- every existing functional spec in the file and its
requireschain, plus - every spec from this batch that has already been inserted.
- Analyze complexity. Run
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 · 120 lines · 97 tokens per session scan A 1948ef2adace
add-functional-specs is a skill published in the GitHub repository plainlang/plain-forge (55 stars, last pushed 4d ago), licensed MIT. It adds 97 tokens to every session and 1,999 once invoked, about $0.0005 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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