check

A command that checks whether a requested feature already exists partly or fully in the project.

In plain words
What is it for?
Use it before planning work such as an export endpoint, JWT authentication, or gateway rate limiting.
Why use it?
It helps prevent rebuilding functionality that is already implemented or currently being developed.

Command

Install

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.

agentmods
npx agentmods add commands/vynazevedo/first-plan/check
Clone the repo
git clone --depth 1 https://github.com/vynazevedo/first-plan
Per session 30 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 760 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
Origin original No closer match found in the catalogue.
Token cost

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.

ModelPer sessionOnce invoked
Fable 5 $0.00030 $0.00760
Opus 5 $0.00015 $0.00380
Sonnet 5 $0.00006 $0.00152
Haiku 4.5 $0.00003 $0.00076

Measured yesterday against content hash 032578368ad6, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

check 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 yesterday.

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.

commands/check.md · 107 lines

How it starts

The opening of the file, as written. The whole thing — 107 lines — stays where its author put it; the contents beside it link to each section on GitHub.

/fp:check

Verificação ad-hoc de duplicidade para uma feature antes de plan.

Argumentos

$ARGUMENTS - descrição da feature em texto livre. Exemplos:

  • "endpoint de export CSV de pedidos"
  • "autenticação via JWT"
  • "rate limiting no gateway"

Workflow

Passo 1 - Pre-flight

Verificar .first-plan/ existe.

Passo 2 - Match contra matriz existente

Aplicar algoritmo da skill reconciliation:

  1. Extrair termos-chave da descrição
  2. Match contra entries em 09-features/INDEX.md por overlap de termos

Se match encontrado: mostrar feature existente + status:

Match encontrado: F5 - "Two-Factor Authentication" (status: IN_PROGRESS)

Detalhes:
- Fonte: JIRA-789
- Confidence: 0.78
- Evidência: branch feat/2fa, PR #42 aberto há 3 dias
- Última atualização: 2026-04-30

Recomendação:
- Esta feature está em progresso. Considerar continuar nesse PR em vez de começar do zero.
- Para ver detalhes: cat .first-plan/09-features/two-factor-authentication.md
- Para colaborar: gh pr checkout 42

Passo 3 - Sem match na matriz - busca direta

Se não match na matriz (pode ser feature nova ou matrix stale):

Spawnar reconciliation-auditor com feature_query=<descrição>:

Task(
  subagent_type="reconciliation-auditor",
  description="Ad-hoc feature check",
  prompt="Audit single feature: '<argumento>'. Apply full classification algorithm against current codebase. Return status + evidence."
)

Passo 4 - Reportar resultado

Caso 1 - feature realmente nova:

"<descrição>" parece ser feature nova - sem evidência de implementação ou spec.

Status sugerido se planejar: NOT_STARTED
Próximo passo: /fp:plan "<descrição>"

Caso 2 - feature existente que não estava na matriz (matrix stale):

Encontrei evidência da feature mas não estava em 09-features/.

Evidência:
- internal/handler/export.go:45 (handler já existe)
- internal/handler/export_test.go (com tests)

Status inferido: IMPLEMENTED (confidence 0.78)

Sugestão:
- Não duplicar - feature parece já existir
- Atualize a matriz: /fp:refresh 09-features
- Se quer modificar a feature existente, especifique melhor o que deseja

Read the full file on GitHub · 107 lines

Changes

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.

  1. yesterday First seen · 107 lines · 30 tokens per session scan A 032578368ad6

Subscribe to this mod's changes

check is a command published in the GitHub repository vynazevedo/first-plan (23 stars, last pushed 7d ago), licensed MIT. It adds 30 tokens to every session and 760 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.