get_design_info

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

The readOnlyHint annotation already tells the agent this is a non-mutating read, so the description only needs to add scope, which it does by specifying the 'active' design and framing the result as counts rather than full data. It does not disclose what happens when no design is open or how large the summary is, but with an output schema present the return shape is covered elsewhere.

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?

A single sentence, front-loaded with the verb and resource, followed by the exact fields returned. Every clause carries information; nothing is repeated from the name or title.

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 zero-parameter, read-only summary tool with an output schema and a readOnlyHint annotation, the description covers purpose and scope adequately. The only meaningful omission is behavior when no active design exists, which an agent might want to know before calling.

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 tool takes zero parameters, so there is no parameter semantics to explain and the description correctly spends no words on inputs. Baseline 4 applies for a no-argument tool.

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 uses a specific verb ('Summarize') and resource ('the active Fusion design'), then enumerates exactly what the summary contains: document name, units, and counts of components, bodies, sketches, features and user parameters. That enumeration makes it easily distinguishable from siblings like list_parameters or set_parameter, though it never names a sibling explicitly.

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?

There is no guidance on when to call this versus alternatives such as list_parameters, which overlaps on the user-parameters portion of the output. The word 'active' implicitly scopes it to the currently open document, but no preconditions (e.g., a design must be open) or exclusions are stated.

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