Mechanical: Inspect Part

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

Annotations already declare readOnlyHint=true, and the description consistently reinforces this with 'Never modifies the drawing' while adding genuinely new behavioral context: the payload version, the views drawn so far, and specific refusal conditions (unknown part_id, missing/foreign/corrupt payload, ambiguous part_id=None). The refusal enumeration is the kind of failure-mode detail annotations cannot express.

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?

Front-loaded with the core purpose, then returns, then refusal conditions. Dense but every clause earns its place; the only mild cost is that the refusal list reads as a run-on enumeration.

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?

With an output schema present, the description need not detail return format, yet it names the return shape and enumerates the error cases. For a single-parameter read-only tool this is close to complete, missing only explicit routing guidance against siblings.

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% so the schema already documents part_id. The description goes beyond it by explaining the failure mode of part_id=None (refused when the drawing holds no part or more than one, with the message listing handles), adding meaningful semantics the schema does not carry.

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 resource and outcome: decoding the ACADMCP_MECH payload a drawn part carries, and it names mech_part_draw as the counterpart whose input it mirrors. The verb 'inspect' is implied rather than stated outright, but the resource and scope are unambiguous enough for an agent to distinguish it from mech_part_draw (write) and mech_view_add.

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?

It ties itself to mech_part_draw by saying it returns the model 'exactly as mech_part_draw accepts it', which implies this is the read-back counterpart, but it never states when to reach for this tool versus alternatives. Usage is only implied through the sibling reference, with no explicit when/when-not guidance.

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