download_attachment

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

Beyond the readOnlyHint annotation, the description discloses that the return value is `content_base64`, explains the remote-server rationale (so no local file path), and instructs the agent to decode it. This is rich behavioral context that the annotations alone do not provide.

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 no filler. The first sentence states the purpose and prerequisite; the second adds essential output format and decoding instruction. Every clause 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 one-parameter, read-only tool with no output schema, the description covers purpose, input source, output format, and processing guidance. Nothing important is missing, and the agent can invoke and understand the result without additional assumptions.

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 schema description coverage at 0% and only one parameter, the description compensates by indicating that `attachment_key` is obtained from list_attachments, which guides the agent on where to find valid values. It doesn't describe format or type, but the guidance is meaningful and more than the schema offers.

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 the action ('Download') and the resource ('an attachment's file content'), and references list_attachments for keys, which distinguishes it from the sibling tool list_attachments (which lists metadata) and upload_attachment (which uploads). It is unambiguous and specific.

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 explicitly tells the agent to see list_attachments for keys, establishing a prerequisite and usage context. It does not explicitly list alternatives or exclusions, but the context is clear: use this after obtaining a key from list_attachments.

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