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

Annotations already declare this is a non-readonly, non-idempotent, non-destructive write. The description adds real value beyond them by explaining why expectedSpecVersion exists (preventing stale writes), but it omits the fact that a configure call replaces the existing legend and that passing null disables it — both relevant to a mutation.

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 short sentences, front-loaded with the action and followed by the key constraint; nothing is wasted. It is close to minimal, erring on the terse side rather than padded.

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 tool with a deep nested legend schema and no output schema, the description is thin: it omits the replace-vs-merge semantics, the null-to-disable behavior, and any note on what is returned. Adequate to identify the action, but not complete for confident invocation.

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?

Top-level schema description coverage is 0% (projectId, expectedSpecVersion and input carry no descriptions), so the description must compensate. It clarifies expectedSpecVersion's purpose but says nothing about projectId or the shape of input, leaving two of three required parameters dependent on the JSON schema alone.

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: configuring the legend of a project map plus its entries. Among siblings like configure_bubbles, configure_camera, configure_popup and configure_search the resource word "legend" makes it easy to tell apart, though the description never names a sibling or scope boundary 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 when-to-use guidance, no preconditions (e.g. layer must already exist), and no routing against alternatives such as update_layer_style, which could plausibly be confused with legend styling. The second sentence is a concurrency constraint, not usage guidance.

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