s3_complete_multipart_upload

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

Annotations already cover read-only (false), idempotent (true), and non-destructive (false) hints. The description adds the behavioral requirement that parts must be provided in ascending order, which is useful, but it does not disclose other traits such as error behavior or effects of retries. This is acceptable given the 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?

Two short sentences: the first states the action, the second states the critical input requirement. Zero filler, front-loaded with the core action.

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 complete parameter schema, the no-output-schema case, and annotations covering safety and idempotency, this description provides sufficient context for an agent to invoke the tool correctly. It could be slightly richer on error cases or return values, but nothing essential is missing.

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 parameters are already well-documented. The description's mention of ETags and ordering adds a minor contextual layer but does not introduce new information beyond what the schema states.

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 'Finalize' with the resource 'S3-compatible multipart upload', clearly distinguishing it from create/abort operations. It also adds a key requirement ('Provide the ETags... in order') that solidifies its purpose.

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?

Usage is implied: the tool finalizes an upload, which presupposes that all parts have been uploaded. It does not explicitly mention alternatives like abort_multipart_upload or state conditions for when to use this over other tools, but the context makes the primary use case clear.

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