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

Annotations already declare readOnlyHint, openWorldHint, and idempotentHint, but the description adds valuable behavioral context beyond those: it returns inline image content blocks, falls back to imageURL when dedicated image delivery is unavailable, and has no filesystem side-effects. This meaningfully informs an agent about expected behavior.

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 two sentences with no filler. It front-loads the primary purpose, then adds the fallback behavior and side-effect guarantee, each earning its place without redundancy.

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 tool with only two parameters, full schema coverage, an output schema, and safety annotations, the description covers the core operation, the response format, fallback behavior, and side-effects. Minor gaps remain around error handling and how missing or invalid imageDbIds are treated, but these are not critical given the output schema and annotations.

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 fully documents both parameters. The description only restates that up to 5 imageDbIds are accepted, matching the schema's maxItems constraint, and does not add deeper parameter semantics such as format, lookup rules, or interaction between alias and imageDbIds.

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 and resource: 'Fetch image bytes for up to 5 imageDbIds and return them inline as `type: image` content blocks.' This clearly distinguishes the tool from siblings like brapi_find_images, which focus on discovering image metadata rather than retrieving image content.

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 implies when to use the tool: whenever image bytes are needed for known imageDbIds. It also mentions a fallback to metadata imageURL, which gives some context about server capabilities, but it does not explicitly say when to prefer this over sibling tools such as brapi_raw_get or brapi_find_images.

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