# `tool` Source: [`src/tool.ts`](https://github.com/AI-for-dev/combo/blob/main/src/tool.ts) The constant parts of a tool combo defines: whether an agent asked for it, and the two shapes of answer a model reads. Three tools - the verdict, the board, the subagent - each wrote these three lines for themselves, once identically and twice inline. A tool body should be the decision it records or the act it performs, and nothing else. ## `declares` *function* ```typescript export function declares(tools: readonly string[] | undefined, name: string): boolean { /* … */ } ``` Whether an agent's `tools:` names `name`. The agent's file is the allowlist: pi enables a custom tool only when the definition names it, so a tool is offered to whoever declares it and costs nothing to offer otherwise. What an agent can do stays readable in its file. ## `refuse` *function* ```typescript export function refuse(text: string) { /* … */ } ``` A refusal the model can act on, rather than a failure it has to guess at. ## `said` *function* ```typescript export function said(text: string) { /* … */ } ``` An answer the model reads as an answer.