s3_put_object

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

Annotations already cover read-only status, idempotency, and destructiveness. The description adds useful behavioral context beyond annotations: the 1 MiB size limit, the inline nature of the upload, and the fact that presigned URLs keep bytes from passing through the server. It does not detail overwrite/versioning behavior, but the annotations lower the burden here.

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 three compact sentences with no filler. The purpose and size constraint are front-loaded, followed by parameter options and routing to alternatives. 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?

Given high schema coverage, present annotations, and no output schema, the description covers the core decision space well: size threshold, inline vs. presigned, and multipart alternative. It could be slightly more explicit that content or filePath must actually be supplied despite only bucket and key being marked required in the schema, but the imperative 'Provide base64-encoded content or a local file path' substantially mitigates that gap.

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 documents all nine parameters. The description adds marginal value by clarifying that content is base64-encoded and that either base64 content or a local file path can be provided, but it does not need to compensate for missing schema documentation.

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 ('Upload'), a specific resource ('a SMALL object inline (≤1 MiB) to a B2 bucket'), and the intended use cases ('manifests, sidecars, and tiny configs'). It distinguishes this tool from s3_get_presigned_url and multipart upload tools, so an agent can tell them apart without opening schemas.

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 states when to use this tool (SMALL inline objects ≤1 MiB) and when not to ('For real object data, generate a PutObject URL... or use the multipart tools for large objects'). It names the specific alternative tools and the condition that selects between them, leaving little to inference.

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