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

Annotations indicate readOnlyHint=false, which already signals mutation. The description adds that it uses 'expo install' and may attach usage instructions, but does not disclose side effects like package.json changes, network access, or failure behavior. With limited annotation support, this is moderate disclosure.

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?

The description is a single sentence, front-loaded with the action and method, and contains no unnecessary words. It is highly concise and structured effectively.

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 simple two-parameter tool, the description covers the core action but omits return value, error handling, and side effects. With no output schema and minimal annotations, it is adequate but incomplete for an agent to fully anticipate the tool's behavior.

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?

Both parameters (libraryName, projectRoot) have 0% schema description coverage, and the description does not explain their format or relationship. It only implies that a library is added to a project, leaving parameter meaning largely to inference from parameter names.

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 action: 'Add an Expo library to the project using expo install'. The verb 'Add' and resource 'Expo library' are specific, and mentioning 'expo install' distinguishes it from documentation or workflow tools among the siblings.

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 description implies use when you want to install an Expo library, but it does not explicitly state when to use this tool versus alternatives (e.g., manual installation or expo_read_documentation). It provides context but no exclusions or alternative guidance.

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