get_attachment

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

Beyond the readOnlyHint and idempotentHint annotations, the description adds critical behavior: the 25 MB decoded size limit, the distinction between images (returned as image content) and other files (base64 in structured output), and that metadata is included. These details inform the agent about output format and constraints not present in 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?

The description is two sentences, front-loaded with the main purpose, then packed with essential details (size limit, output format, alternative). No wasted words; every sentence earns its place.

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 tool with a full input schema and an output schema, the description covers the key context needed: size limit, output type differentiation, and the alternative for large attachments. It is complete for the tool's complexity.

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 baseline is 3 per the rubric. The description does not add per-parameter semantics beyond what the schema provides, but it does describe the overall behavior of fetching content, which indirectly clarifies the purpose of the parameters.

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 clearly states 'Fetch one attachment's content into the conversation', using a specific verb and resource, and distinguishes itself from siblings by mentioning when to use save_attachment instead. It also specifies the scope ('one attachment') and the context (into the conversation).

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?

Provides explicit guidance on when to use this tool vs alternatives: 'For an attachment too large to be worth reading inline, use save_attachment instead.' This is a clear when-not/alternative directive. The description also implies its use case as inline reading of attachment content.

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