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 adds real value beyond that by disclosing the return shape: reviewer notes as text plus each annotated screenshot as an image, which matters because no output schema exists.

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 with zero filler, front-loading the action and identifier before the payoff of what you get back.

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 single-parameter tool, the description covers the action, the input form, and the return composition (text notes + annotated images), which compensates for the absent output schema. Only minor gaps remain, such as failure behavior for invalid links.

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?

With a single parameter at 100% schema description coverage, the schema already documents the accepted URL formats and bare slug. The description's 'share link or slug' adds no syntax or format 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?

The description states a specific verb (Fetch) and resource (a Cobalt Capture review), and specifies the identifier type (share link or slug). It is clearly distinct from write-oriented siblings like create_review and update_review, though it never names an alternative reader.

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?

'Fetch ... by its share link or slug' implies the retrieval use case, and the closing clause hints at the goal (see what was marked and what to change). However, there is no explicit when-to-use/when-not guidance and no mention of alternatives such as search or fetch.

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