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

Annotations already cover readOnlyHint and idempotentHint; the description goes beyond them by disclosing the retrospective, named-case perspective, the 'seven' file scope, and the caveat that no cohort recall percentage should be quoted. It also specifies the two behavioral modes (summary vs full case file) without contradicting the read-only annotation.

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 dense sentences, front-loaded with the tool's purpose before usage instructions, with no redundant filler. The phrase 'through unrecalibrated Indian lenses' is compact but somewhat opaque, slightly reducing immediate comprehensibility for an agent.

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 one-optional-parameter read tool with strong annotations, this is nearly complete: it defines both call modes and the key methodological caveat. The lack of an output schema means the return shape is only described at a high level (summaries vs full quarterly case file), and 'unrecalibrated Indian lenses' is left unexplained, but an agent can still invoke it correctly.

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 coverage is 100%, so the schema already documents the optional slug; the description adds the key semantic distinction that omitting the slug yields summaries while supplying a returned slug yields a full quarterly case file. The phrase 'returned slug' adds implicit provenance beyond the schema's generic optional-string description, though it could be clearer about whether any valid slug is accepted.

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?

Opens with a specific verb+resource: 'Read seven cited European retrospective case files,' naming the geographic scope and file type. The second sentence reinforces the distinction from cohort-style siblings ('Named case studies, not a cohort'), so an agent can distinguish it from evidence_us/evidence_india and aggregate tools.

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?

Gives concrete invocation guidance: omit slug for summaries, supply a returned slug for a full quarterly case file. It states a clear when-not ('no European recall percentage to quote') but does not explicitly name alternative tools or conditions for choosing them, relying on sibling names and domain to make the selection clear.

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