download_file

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

With no annotations provided, the description carries the full burden. It explicitly discloses that the tool returns content inline as base64 and refuses files larger than max_bytes instead of writing to disk, which conveys a non-persistent, read-only behavioral profile. It does not mention side effects beyond disk write avoidance, but this is meaningful behavioral context beyond the schema.

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 concise sentences with zero filler. The primary action and output format are front-loaded, followed by the limiting behavior. Every word adds value.

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?

Given the lack of an output schema, the description adequately explains the return format (base64) and the key constraint (max_bytes refusal). It does not detail error cases or auth requirements, but for a simple single-file fetch tool with only integer parameters, the essential information is present. The disk-free note also covers a common concern for download tools.

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 each parameter already has a clear description. The tool description mentions max_bytes and its refusal behavior, but this directly mirrors the schema description, adding no new semantic information. The baseline of 3 applies because 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?

The description uses a specific verb ('Fetch'), a specific resource ('one attachment'), and the output format ('inline as base64'). It clearly distinguishes itself from siblings like upload_file and get_task_files by indicating it retrieves a single attachment's content rather than listing or uploading.

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 usage ('Fetch one attachment') but does not explicitly state when to use it versus alternatives, such as after calling get_task_files to obtain file_id. There are no exclusion rules or references to sibling tools, so the agent must infer the appropriate context.

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