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 break-down-func-specgit 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/break-down-func-spec)<a href="https://agentmods.dev/skills/plainlang/plain-forge/break-down-func-spec"><img src="https://agentmods.dev/badge/skills/plainlang/plain-forge/break-down-func-spec/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/break-down-func-spec"><img src="https://agentmods.dev/badge/skills/plainlang/plain-forge/break-down-func-spec.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 | $0.00057 | $0.02170 |
| Opus 5.5 | $0.00023 | $0.00868 |
| Sonnet 5.5 | $0.00011 | $0.00434 |
| Haiku 4.5 | $0.00006 | $0.00217 |
Grade A, and why
break-down-func-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 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 — 207 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Break Down Functional Spec
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
analyze-if-func-spec-too-complexflagged a spec as TOO COMPLEX.- A spec is suspected of exceeding the 200 LOC limit and needs to be split preemptively.
- A spec bundles multiple behaviors, constructs, or concerns that should be separated.
Input
The functional spec to break down, plus the full .plain file it belongs to.
Workflow
- Read the full
.plainfile — definitions, implementation reqs, and all functional specs (includingrequiresmodules) to understand context. - Identify the spec to break down — the one flagged as too complex or pointed to by the user.
- Analyze why it is too complex — use the indicators from
analyze-if-func-spec-too-complex:- Multiple distinct behaviors bundled together?
- Too many new constructs introduced at once?
- Complex branching logic or conditional paths?
- Cross-cutting concerns mixed with core functionality?
- A full UI screen described in one spec?
- Complex data transformations across multiple entities?
- Implies one substantial technical component (engine, parser, scheduler, algorithm, state machine, sync mechanism) that must be built in code?
- Identify the split boundaries — find the natural seams where the spec can be divided. Each resulting spec must be:
- Independently meaningful (makes sense on its own with previous specs as context)
- Self-contained (does not require a later spec to be useful)
- Within the 200 LOC limit
- Draft the replacement specs — write the smaller specs in chronological order. The first replacement spec typically sets up the foundation, and subsequent ones layer behavior on top.
- Verify functional completeness — this is critical. The replacement specs taken together must cover 100% of the functionality described in the original spec. Walk through every behavior, condition, and detail in the original and confirm it appears in exactly one of the replacement specs. Nothing may be lost, weakened, or left implicit. If any functionality from the original is missing, add it to the appropriate replacement spec or create an additional one.
- Verify each replacement spec — run
analyze-if-func-spec-too-complexon each to confirm it fits within the limit. - Check for conflicts — run
analyze-func-specsonce with the full set of replacement specs plus every existing spec in the file and itsrequireschain. The batched analyzer reports every conflicting pair (replacement × existing and replacement × replacement) in one call — do not loop over pairs. Resolve each reported pair withresolve-spec-conflict, then re-runanalyze-func-specsover the touched set until the verdict isCOMPATIBLE. - Replace in the file — remove the original spec and insert the replacement specs in its position, preserving chronological order.
- Read the file again to confirm correct placement and syntax.
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 · 207 lines · 57 tokens per session scan A 0448c2cda983
break-down-func-spec is a skill published in the GitHub repository plainlang/plain-forge (79 stars, last pushed yesterday), licensed MIT. It adds 57 tokens to every session and 2,170 once invoked, about $0.0002 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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