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

Annotations already declare readOnlyHint=true, destructiveHint=false and openWorldHint=false, so safety is covered. The description goes further by disclosing plan-dependent response content: free accounts receive every event while Pro unlocks the playbook, sourced numbers and sources — a behavioral trait an agent cannot infer from the 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?

Two tight sentences, front-loaded with the resource and its returned artifacts, with no filler. The second sentence is dense but each clause carries distinct information about what is and isn't available.

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?

There is no output schema, so the description carries the return-value burden and does so well by naming the timeline stages, Spread Score, citation and tier-gated extras. It omits failure behavior (e.g. unknown slug) and any pagination/size note, which keeps it short of a 5 for a read tool.

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% and the single slug parameter is already documented as 'The case slug from search_cases'. The description adds no format, casing or validity detail beyond that, so the 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?

States a specific resource (one case) and enumerates its payload — dated spread timeline, Spread Score, citation, plus tier-gated playbook and sources. The singular 'One case' implicitly contrasts with the list-shaped sibling search_cases, but no sibling is named, so the distinction is inferred rather than stated.

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 contains no when-to-use or when-not-to-use guidance and never mentions search_cases or list_mechanics. The only routing hint — that the slug comes from search_cases — lives in the input schema, not the description, so an agent gets no in-description workflow direction.

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