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

Annotations only declare a safe read-only, non-open-world operation; the description goes further by disclosing what is included and excluded from the measurement (DNP parts omitted, parts with missing 3D models excluded from volume and reported separately). That is real behavioral context an agent cannot infer from readOnlyHint alone, though nothing is said about job timing or failure modes.

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 dense sentences that front-load the action and then the output definition; the formula is worth its characters because it defines the tool's core value. It is slightly run-on and could be split for readability, but there is no filler.

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 no output schema, the description takes on the return-value burden and does so thoroughly: it names every reported quantity and the missing-3D-model list. Combined with the schema's wait_s/job-polling note, an agent has everything needed to call it and interpret the result.

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% for both parameters, including the design_id source and the wait_s/get_board_job follow-up, so the schema carries the parameter burden. The description adds no syntax, defaults, or format guidance beyond it, which is the expected baseline when coverage is complete.

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+resource pair (export the assembled board, measure it) and then enumerates the exact metrics produced: bounding-box size, volume, via count, copper layers, and a named composite score with its formula. That formula makes it trivially distinguishable from siblings like board_census or get_board_info, which cannot return this metric.

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 implies usage (you want the PCBGolf score / board measurement) but never states when to prefer this over board_census, get_board_info, or export_step, nor any prerequisites. The only routing guidance in the toolset lives in the schema's wait_s text pointing to get_board_job, not in the description.

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