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

With no annotations, the description carries the full behavioral burden and does so well: it declares read-only and no-auth operation, explains result semantics like port_exhausted versus unknown, and warns that the returned caliber field is not interchangeable with check_compatibility. These details go well beyond what the input schema provides and prevent unsafe or incorrect interpretation.

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 front-loaded with the core purpose and structured into distinct sections for sibling differentiation, result semantics, and parameter modes. It is longer than a minimal definition, but most sentences carry useful meaning; some of the star/bold formatting is dense rather than strictly necessary.

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?

There is no output schema, so the description must compensate for return-value information. It mentions key result fields and statuses such as caliber, evidence chain, port_exhausted, and unknown, but does not fully specify the complete response shape, leaving a modest gap for an agent trying to anticipate output structure.

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 description coverage is 100%, so the individual parameters are already documented. The description still adds meaningful semantics by explaining how host, a, and b combine to produce different result modes, which supplements the schema's field-level descriptions.

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 states a specific operation on a specific resource — querying the triadic co-mount relation (A↔host↔B) and whether one robot body can host two components simultaneously. It explicitly distinguishes this from the sibling check_compatibility, which handles two-way A-into-B insertion, so an agent can select correctly without opening schemas.

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 explicit when-to-use guidance and alternatives: use this for co-mount questions, while check_compatibility answers a different two-segment insertion question. It also maps parameter combinations to behavior: host+a+b for one pair ruling, host only for single-item fit plus tool-side evidence, and no params for a layer summary.

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