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

Annotations already provide readOnlyHint=true, and the description goes beyond that by disclosing the publication filter (confidence >= 0.7, verbatim evidence), the pricing tier, and the fact that edges are 'checkable rather than asserted.' These are useful behavioral facts not present in the annotations. Minor omissions like pagination are acceptable given the read-only hint.

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 more elaborate than strictly necessary, but every sentence contributes: purpose, edge contents, filtering rule, citation use case, plan, pricing, and price reference. It is front-loaded with the core purpose and only minor redundancy exists around 'UNDERSTANDING' and 'Understanding plan.'

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 read-only lookup tool with only one required parameter and no output schema, the description is thorough: it names all returned edge fields, explains the confidence threshold, addresses empty-result plausibility by noting only published edges appear, and even covers pricing. It does not specify sorting or pagination, but those are not critical for correct 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?

Schema description coverage is 100%, so the schema already documents 'capability' and 'context' fully. The description reinforces that the capability is the central lookup target and explains the evidence structure, but it does not add parameter-level semantics beyond what the schema provides. Baseline 3 applies.

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 opens with 'UNDERSTANDING — the evidence behind a capability' and then enumerates precisely what an edge contains: provider, tag, OpenAPI file, confidence, and quoted contract fragment. It clearly distinguishes this from sibling tools like get_capability or find_capabilities by positioning it as the checkable evidence source for a capability claim.

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 gives an explicit use case: 'This is what you cite when someone asks "says who?"' which tells an agent when to select this tool. It does not name alternative tools or state when not to use it, but the scenario is specific enough to be actionable.

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