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

The annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, so the agent knows this is a safe, idempotent read operation. The description adds no new behavioral traits beyond confirming it lists commitments. It does not discuss rate limits, permissions, or response format (though output schema exists). The description meets the baseline given annotation coverage but adds minimal extra value.

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 extremely concise: two sentences, no fluff. The first sentence states the action and expected output, the second states requirements. Every word adds value. It is front-loaded with the core purpose.

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?

Given the tool's simplicity, the presence of a full output schema, and annotations covering safety, the description is complete. It explains what the tool does, what it returns (details), and what inputs are required. Pagination parameters are in the schema. There is no missing information that would hinder correct invocation.

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% with descriptions for all four parameters (project, region, pageSize, pageToken). The description merely restates that project and region are required, which is already in the schema. No additional semantics or clarification about parameter values (e.g., region format, pageToken usage) are provided. The baseline score of 3 is appropriate since the schema does the heavy lifting.

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 Compute Engine Commitments in a region, specifying the exact resource type (commitments) and the context (region). It enumerates the details returned (name, ID, status, etc.), which unambiguously identifies the tool's purpose. This distinguishes it from sibling tools like list_commitment_reservations, which list a different sub-resource.

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 provides clear context by stating the tool requires project and region as input, which implies it should be used when the agent needs to list commitments within a specific project and region. However, it does not explicitly mention when not to use it or provide alternative tools for different scopes (e.g., list_disks for disks). Still, the context is sufficient for an informed agent.

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