gemini_agents

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already declare readOnlyHint and openWorldHint, so safety is covered; the description still adds useful context that the call is 'free and quick' and that returned names feed into gemini_code's `agent` parameter. It also discloses the empty-state message, which helps an agent interpret a sparse result.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

Front-loaded with purpose, then usage, then returns; two short paragraphs with little waste. The 'Returns' block is partly redundant with the declared output schema, but the empty-state string and the handoff to gemini_code earn most of its space.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a parameterless, read-only discovery tool with an output schema, the description covers what it lists, when to use it, and what an empty result looks like. Nothing essential for correct invocation appears to be missing.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Zero parameters, so this dimension is at its baseline; the schema is trivially complete. The description does not need to explain any input, and the note about passing a name as `agent` to gemini_code clarifies downstream usage without inventing input semantics.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

States a specific verb and resource ('List the custom Antigravity agents the user has made or installed') and gives a concrete example ('reviewer' or 'test-writer' agent with its own instructions), which differentiates it from generative siblings like gemini_code.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

Explicitly says to call it before gemini_code when the user wants a task done by a specific agent, giving a clear trigger and ordering relative to the main sibling. It stops short of stating when not to call it (e.g., no need for discovery if the user already named an agent).

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.