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

No annotations are provided, so the description must disclose behavior. It mentions the return format ('JSON string with CLI availability status') but does not explicitly state that the tool has no side effects, whether it requires any setup, or how it behaves if the CLI is not installed. The word 'check' implies read-only, but this is not explicitly stated. It provides basic transparency but could be more explicit about safety.

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 two short sentences, front-loaded with the main action and then the return type. No unnecessary words or redundancy. It is highly concise and well-structured.

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 no-parameter check tool with an output schema, the description covers the essential information: what it does and what it returns. It could optionally mention the relationship to install_blocks_cli, but the core information is sufficient. The context signals indicate low complexity, so completeness is adequate.

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 has zero parameters, so schema coverage is trivially 100%. The description does not need to explain parameter meaning. Baseline for 0 params is 4, and nothing in the description reduces this.

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 it 'Check if Blocks CLI is installed and available.' The verb 'check' plus the resource 'Blocks CLI' make the purpose explicit. It is also distinguishable from sibling tools, especially install_blocks_cli, by focusing on verifying installation instead of installing.

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 gives no guidance on when to use this tool versus alternatives. It does not mention, for example, to use this before attempting to run CLI commands or to call install_blocks_cli if the check returns unavailable. There is no context about prerequisites or expected workflow.

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