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

Annotations already declare readOnlyHint=true and idempotentHint=true, and the description remains consistent with these. It adds valuable behavioral context about authentication requirements ('Requires an access right on EVERY robot listed') and partial-failure semantics ('returns a refusal naming it, and compares nothing'), which goes beyond the structured fields.

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 tightly written sentences front-load the purpose and follow up with the most important usage constraint. Every clause earns its place with no fluff.

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 single-parameter comparison tool with no output schema, the description covers purpose, scope bounds, and the critical access-control failure case. It does not describe the return shape, but given the simple read-only profile, the description is reasonably complete.

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 only parameter, robot_ids, has 0% schema description coverage, and the description only implies arity ('2 to 5 robots') without specifying the string format or how IDs are delimited. The description only marginally compensates for the schema gap, so an agent would still have to guess whether IDs are comma-separated, JSON-encoded, etc.

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?

Description uses the specific verb 'compare' with a clear resource and scope: 'Compare 2 to 5 robots side by side on mechanical BOM, specifications, risk and geographic exposure.' The 'mechanical' qualifier distinguishes this from hardware_compare_robots and software_compare_robots, and the arity constraint adds precision.

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 clear context on when to use it via the access-right prerequisite and failure mode ('Requires an access right on EVERY robot listed; if one is missing the call returns a refusal naming it, and compares nothing'). However, it never explicitly names an alternative tool or states when NOT to use this versus siblings, so usage guidance is implied rather than explicit.

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