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

The description goes beyond the readOnlyHint annotation by disclosing that a valid access token is required, that the explanation appears attributed to the agent, and that the tool automatically pauses 3–15 seconds before returning. It also warns against adding artificial delays—all valuable behavioral context not captured in annotations.

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?

The description is well-structured and front-loaded with the core purpose. Each sentence adds unique value: purpose, usage, non-mutation, auth, and delay behavior. The IMPORTANT note is clearly highlighted, making the message easy to parse without wasted words.

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 no output schema, the description adequately explains the effect (UI attribution, non-mutation) and the unique delay behavior. It also covers prerequisites (token) and usage constraints (no artificial delays). All key aspects are addressed given the tool's complexity.

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 every parameter already has a rich description. The tool description adds only minimal extra context (e.g., anchoring to a node matches entityId, auth requirement matches token), which does not meaningfully supplement the schema. Baseline of 3 is appropriate.

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 clearly states the tool delivers an explanation payload to human collaborators, with specific use cases ('explain what a diagram element represents, why it exists, or how it relates to other parts of the system'). It explicitly differentiates from mutation tools by noting it does NOT mutate the diagram and is for use 'without suggesting a change', distinguishing it from siblings like make_suggestion.

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 provides explicit when-to-use context ('Use this when you want to explain...') and a when-not ('without suggesting a change'). It also includes practical guidance about not adding artificial delays. However, it does not explicitly name alternative sibling tools for scenarios like suggesting changes, so it falls short of a 5.

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