s3_copy_object

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

The description adds useful behavioral context beyond the annotations: the acl parameter is called out as a no-op S3 compatibility hint, and B2 access is tied to the destination bucket policy. This helps the agent understand side effects and authorization behavior that the annotations do not convey. There is no contradiction with 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 with no filler. It front-loads the core operation and scope, then places the important acl caveat and access-policy note. Every sentence earns its place and the structure is easy for an agent to scan.

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 9-parameter tool with full schema coverage and useful annotations, the description is reasonably complete: it clarifies bucket scope and the acl no-op. It does not describe the return value or error behavior, but the absence of an output schema and the schema's thorough parameter documentation keeps this from being a major 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 parameter meanings. The description repeats the acl no-op behavior that the schema already states, adding no new param-level insight. Baseline 3 is appropriate because the schema does the heavy lifting and the description does not need to compensate.

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 operation: 'Copy an object within B2 or between B2 buckets via B2's S3-compatible CopyObject API.' It names a specific verb, resource, and scope, and the phrase 'CopyObject API' distinguishes it from sibling upload/part-copy tools without requiring schema inspection.

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 gives clear context for the operation and its cross-bucket scope, but it never explicitly tells the agent when to choose this over alternatives like s3_put_object or s3_upload_part_copy. Usage is implied by the semantics of 'copy' rather than stated with exclusions or sibling comparisons.

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