b2_update_file_retention

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

Annotations already mark this as destructive and non-read-only; the description adds useful behavior beyond that, such as 'In compliance mode, the retain-until date can only be extended' and the required writeFileRetentions capability. There is no contradiction with annotations. It could include more side-effect detail, but the provided context is meaningful.

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?

Three short sentences carry the essential information: purpose, mode support, compliance constraint, and capability requirement. Every sentence earns its place with no filler or repetition.

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 plus the richly documented schema cover the core operation, prerequisites, mode restrictions, required parameters, and the confirm behavior. There is no output schema, but for a mutation tool this is acceptable. A minor gap is that the description does not explicitly summarize clearing behavior, though the 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 the baseline is 3. The description adds extra parameter-relevant meaning: the compliance mode only allows extending retain-until, and the capability requirement affects whether certain operations are permitted. This goes beyond what the schema's property descriptions state.

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 opens with 'Set or modify the retention policy on a specific file version in B2,' naming the action, the resource, and the scope precisely. It also names the two supported retention modes, distinguishing this from legal-hold and bucket-level operations. This is specific and non-tautological.

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 clearly establishes when the tool is applicable—when a B2 file version's retention policy needs to be set or modified—and adds the capability prerequisite. It does not explicitly name alternative tools, but the operation scope and sibling names make the intended use unambiguous. The schema covers the confirm flag for destructive operations.

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