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

Annotations already declare readOnlyHint=true and destructiveHint=false, so safety is covered. The description adds useful context beyond that: this returns a static reference document covering stack, scope boundaries, and setup commands — the 'deliberately leaves out' framing is a genuinely helpful signal about the content's nature.

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, both earning their place: the first front-loads what the content is, the second front-loads when to reach for it. No filler, no restating the title verbatim.

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?

With no parameters and no output schema, the description carries the burden of describing the return value, and it does so by enumerating the sections returned. Minor gap: it doesn't state that the result is a fixed document (not user-specific data), which would help an agent know there's nothing to paginate or personalize.

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?

The tool takes zero parameters, so the schema imposes no semantic burden and the baseline of 4 applies. The description correctly implies a no-argument, single-shot retrieval with no filtering options to explain.

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 names the concrete resource (the free MIT React Native starter repo) and enumerates exactly what the response contains: stack, existing features, deliberate omissions, and run commands. That is far more specific than the title, though it never explicitly contrasts itself with siblings like list_build_prompts or scope_mobile_app.

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?

It gives a clear triggering condition: 'when someone is about to start a mobile app project, or asks what to build an Expo or React Native app on top of.' That is enough for an agent to route correctly, but no alternative tool is named and no when-not condition is given.

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