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

Annotations already declare the tool as read-only, idempotent, and non-destructive, so the description does not need to repeat that. It adds useful behavioral context by describing the two output modes and the version-matched nature of the returned operations, which goes beyond the basic safety profile.

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 three sentences long and every sentence earns its place: the first defines the core action, the second explains parameter choices, and the third gives invocation context. It is well-front-loaded and free of redundancy.

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?

Given the lack of an output schema, the description does a good job of outlining what information will be returned (field types, required flags, enum values, defaults, constraints) and when to call it. However, it does not specify the exact return format (e.g., JSON), which is a minor gap for an agent that needs to parse the response.

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 input schema already covers both parameters fully (100% schema description coverage), so the baseline is 3. The description enhances this by explicitly explaining the purpose of each 'detail' value and how they change the output, which helps the agent choose correctly.

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 returns version-matched mutation operations for a specific diagram family. It distinguishes itself from the sibling tools by explicitly positioning it as a prerequisite for build, mutate, or execute, and the name 'describe_sdk' differentiates it from the generic 'describe' sibling.

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?

Explicit guidance is provided: 'Call this before build, mutate, or execute when the family schema is not already known.' It also instructs when to use each detail mode ('signatures' for compact menu, 'fields' for exact types), making the usage context clear and actionable.

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