List apps

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

Annotations already declare readOnlyHint=true, so the read-only nature is known. The description adds behavioral context by noting the registry is reusable across chats, lists the user's openable apps by default, and allows widening via kind/visibility.

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?

Three sentences, front-loaded with the core purpose, each adding meaningful information: registry scope, the reuse-over-create guideline, and parameter usage. No wasted words or redundancy.

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 read-only list tool with three optional params and no output schema, the description covers the essential context: what is listed, default filtering, lookup behavior, and how to broaden the search. It is self-sufficient and well-rounded.

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?

Schema covers 100% of parameters with descriptions, so baseline is 3. The description adds value by mapping parameters to use cases: 'pass name to look one up' and 'widen with kind/visibility', which clarifies intent beyond enum definitions.

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?

The description clearly states the tool lists UI apps in the registry, with a specific resource ('UI apps') and scope ('reusable across all chats'). It distinguishes itself from creating or opening apps by framing the registry as a lookup surface.

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?

Provides explicit guidance: 'prefer opening it over creating a new one' and explains how to narrow results with name or widen with kind/visibility. It does not name sibling tools explicitly but gives enough context for choosing this over a create/open action.

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