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

Annotations already declare readOnlyHint=true, idempotentHint=true, destructiveHint=false and openWorldHint=false, so the safety profile is covered. The description usefully discloses what kind of payload comes back (best practices plus Swift examples across three domains), but says nothing about caching, freshness, or how the truncation behavior interacts with the requested topic. Adequate but not rich.

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?

Two sentences, no filler. The return contract is front-loaded in the first sentence and the invocation modes in the second, so an agent can act after reading the opening clause.

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 guide lookup with no output schema, the description covers subject scope and the empty-argument fallback, which are the two things an agent must know to call it correctly. Minor gaps remain around result freshness and how topic/query interact, but nothing blocking is 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?

Schema coverage is 100%, so the baseline is 3. The description earns an extra point by documenting behavior the schema cannot express: passing nothing returns 'the index of topics', which is a meaningful mode distinction an agent would otherwise have to guess. It still leaves the topic-vs-query selection heuristic to the schema.

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 (Returns) plus the resource (best practices and Swift examples for SwiftUI interfaces) and enumerates the covered domains: layout/view composition, animation and gestures, Metal shader effects. It is clearly a documentation-retrieval tool, though it never distinguishes itself from adjacent guide siblings such as get-motion-guide or get-widget-guide, whose subject matter overlaps with 'animation and gestures'.

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?

The second sentence explains the three input modes ('Pass `topic`, `query`, or nothing for the index of topics'), which implies how to drive the tool, but there is no statement of when to prefer this guide over the sibling guide tools or when it is not appropriate. Usage is inferable rather than prescribed.

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