Give an Agent a new capability¶

An extension packages something your team can reuse: instructions, a tool, an app connection, an evaluator, or a model profile. Start with the smallest piece that solves your problem.

Choose a package type¶

Type	Use it for	Main file
`skill`	Instructions for a repeatable task	`SKILL.md`
`tool`	A named operation with an input schema	`tool.json`
`connector`	An application connection and its permitted events	`connector.json`
`evaluator`	A way to assess a result	`evaluator.json`
`model-profile`	A model's processing route and capabilities	`model-profile.json`
`agent-bundle`	A selection of components for an Agent	`agent-bundle-selection.json`

Create a tool package¶

geyser init tool careful-search
geyser validate careful-search
geyser test careful-search
geyser dev careful-search

The generated directory contains:

geyser-package.json: name, kind, version, and requested permissions.
tool.json: description, input schema, effect class, and approval posture.
evals/cases.json: declared success and denial fixtures.
README.md: a place to explain the package to its next developer.

In 0.1.0, test checks the fixture declarations and dev demonstrates a local admission and completion. Use your own tool tests to exercise its implementation. For an example that actually calls a registered local function, follow the emulator quickstart.

Describe the action clearly¶

Give the tool a name and description that explain what it does. Define its accepted inputs with a schema. Declare whether it reads information or changes another system, and request only the permissions it needs. A package requests access; the workspace decides what it receives.

Write examples for both a useful result and an action the tool should decline. For a result your application needs to parse, add a structured outcome.

Package and connect¶

geyser package careful-search

This creates a local archive and reports its digest. Signing and remote staging come next; see the CLI reference and authentication for the required project access. For a collection of capabilities, use an Agent Bundle.