Get object metadata without downloading its content

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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint=false, so the safety profile is clear. The description adds value by specifying exactly what metadata is returned and confirming no body transfer occurs. 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?

Two sentences that are highly informative and to the point, with no fluff. First sentence defines action and output, second provides cost rationale relative to sibling. Every word contributes.

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?

The description is complete for a simple, safe, read-only operation: it explains what metadata is returned, confirms no body transfer, and provides selection guidance. No output schema exists, but the listed metadata fields suffice. Slight gap: no mention of the region parameter's default behavior, though schema covers it.

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 parameters are fully documented in the schema itself. The description does not add additional parameter details beyond the schema, which is acceptable given high coverage.

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 tool fetches object metadata without downloading content, with specific metadata fields listed (content-type, size, etag, etc.). It distinguishes itself from scaleway_s3_get_object by noting this is cheaper when content is not needed.

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 advises using this over scaleway_s3_get_object when you don't need the content, providing a clear when-to-use scenario. The sibling list includes both tools, and the description directly compares them.

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