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

Beyond the annotations, the description discloses critical behavioral traits: the response is the whole untruncated document, can be extremely large (~800,000 characters / ~200,000 tokens), and returns null for non-federated variants rather than an empty document. These details are essential for an agent to invoke and handle the tool correctly.

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 front-loaded with purpose and includes useful context, but it is somewhat verbose. The size warning is important, though slightly repetitive across sentences. Overall it is appropriately structured for a tool with significant behavioral caveats.

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 rich annotations, the existing output schema, and the detailed description of size, null behavior, and composition metadata, the definition is complete enough for an agent to call the tool correctly. No major contextual gaps remain.

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 schema has 0% description coverage, so the description must clarify the two parameters. It only says 'Provide the graph ID and the variant name,' without explaining expected formats, how to obtain these values, or variant naming conventions. This is minimally viable but leaves gaps.

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 states a specific verb and resource: reading the composed supergraph schema (SDL) for a graph variant, including composition ID and errors. It clearly distinguishes this from the API schema and subgraphs by explaining that supergraph schemas carry federation directives. An agent can tell exactly what this tool retrieves.

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?

It gives clear context for when to use the tool, equating it to `rover supergraph fetch` and noting that non-federated variants return null. However, it does not explicitly name alternatives such as GetGraphSchema or GetSubgraphSchema or state when not to use this tool.

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