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

Annotations already declare readOnlyHint=true, idempotentHint=true, and openWorldHint=false, so the safety profile is covered. The description adds value by enumerating what the response contains ('the evidence links and where the evidence stops'), which is meaningful given there is no output schema, but it says nothing about error behavior for an invalid slug or the size/shape of the payload.

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?

A single front-loaded sentence with no wasted preamble, and the payload enumeration is compact. The phrasing is slightly metaphorical ('where the evidence stops'), which costs a little precision but not length.

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?

With no output schema, the description carries the burden of describing what is returned and does so by listing the major components of a study. For a one-parameter read-only lookup that is nearly sufficient; only the missing routing to list_studies and the undefined invalid-slug behavior keep it from being fully complete.

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% and the single slug parameter is fully documented with an enum of ten valid values and a pointer to list_studies. The description adds no syntax or format detail beyond that, which is the expected baseline when the schema does the heavy lifting.

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 verb and resource — read one study in full — and enumerates the payload components (question, result, design decision, recorded data, evidence links, evidence boundaries). It implicitly contrasts with list_studies by saying 'One study in full', but never names the sibling explicitly, so differentiation is left partly to inference.

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?

There is no statement of when to use this tool versus list_studies, no prerequisite that a slug must first be obtained, and no exclusions. The only routing hint ('from list_studies') lives in the schema's parameter description, not the tool description, so the description itself gives the agent no usage guidance.

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