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

Annotations already declare readOnly/idempotent/non-destructive, but the description adds substantial behavioral context beyond them: the response is untruncated, carries a concrete size benchmark (800,000 characters, ~200,000 tokens), and warns this can exceed most models' context windows. That is exactly the kind of risk disclosure an agent needs before invoking.

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?

Front-loaded with the core purpose, followed by the rover equivalence, the size warning, the alternative, and finally the inputs. Every sentence earns its place and there is no filler.

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?

An output schema exists, so return values need not be re-explained, yet the description still flags hash and publication time plus the document size. Combined with the alternative routing and required inputs, nothing an agent needs to call this correctly is missing.

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 description coverage is 0%, so the schema carries no parameter documentation. The description only says 'Provide the graph ID and the variant name', which maps the two params to their obvious meanings but adds no format, valid-value, or default guidance (e.g., whether variant accepts 'current'). Minimal compensation for a total coverage gap.

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 published SDL schema for a graph variant, returning its hash and publication time. It explicitly distinguishes itself from the sibling GetSubgraphSchema and by extension GetSupergraphSchema, so an agent can route without opening either schema.

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 an explicit preference rule ('Prefer GetSubgraphSchema, which reads one subgraph at a time') and the exact condition for using this tool instead ('only when you need the whole API schema'). It also names the required inputs, so both when-to-use and prerequisites are covered.

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