get_part_definition

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

The annotations already declare readOnly/idempotent/non-destructive, so the safety profile is covered; the description adds the important failure mode ('fails when the definition is not installed') and notes that placement permission is returned with a reason when denied. It does not touch on cost or limits, but it meaningfully extends the structured metadata rather than repeating it.

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?

Three sentences, front-loaded with the return contents, then usage ordering, then the failure condition. The field enumeration is dense but each item is decision-relevant for an agent checking part compatibility; nothing is redundant padding.

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 one-parameter read-only lookup with an output schema (so return shape needn't be spelled out), the description covers purpose, sequencing, alternative tool, and error behavior. Nothing an agent needs in order to call it correctly is missing.

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% and the single 'definition' parameter already documents the id format and points to search_parts. The description only reinforces the search_parts discovery path and adds no new syntax or format detail, so the baseline of 3 applies.

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?

States a specific verb and resource ('Return one installed part's definition') and then enumerates exactly what the payload contains: footprint voxels, attachment/sealing surfaces, logic nodes, settings, mass, seal coverage, placement permission. It also names the sibling (get_part_orientation) that handles rotation, so an agent can distinguish the two without opening either schema.

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?

Gives explicit sequencing ('Use it after search_parts') plus the concrete questions it answers (how a part mounts, connects or seals), and routes the rotation question to get_part_orientation. That is a clear when-to-use plus a named alternative with the condition that selects it.

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