s3_download

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

No annotations are provided, so the description carries the full burden of behavioral disclosure. It reveals that the output is base64-encoded, which is key behavior, but does not mention limitations (e.g., file size, timeout), permissions required, or whether the tool is safe/read-only. The description adds some value beyond the schema but is insufficient for a no-annotation tool.

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 a single sentence that conveys the essential purpose and key detail (base64 encoding). No extraneous information. Efficient and well-structured.

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 tool has 2 parameters, no output schema, and no annotations, the description is minimal but covers the core functionality. However, it lacks details on error handling, default bucket behavior, or size limits. For a simple download tool, it is adequate but not comprehensive.

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?

The input schema provides descriptions for both parameters ('key' and 'bucket') with 100% coverage. The description does not add new meaning beyond the schema; it only restates the purpose. Baseline 3 is appropriate.

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 explicitly states 'Download an object from S3 and return it base64-encoded', which is a specific verb ('download'), resource ('S3 object'), and adds detail about encoding. This clearly distinguishes it from sibling tools like s3_upload (upload) and other non-S3 tools.

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?

No guidance is provided on when to use this tool versus alternatives. For example, it does not mention that this is for small objects due to base64 encoding, or contrast with other data access tools like dynamo_read. The description lacks context for when this tool is appropriate.

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