b2_list_buckets

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

The annotations already provide readOnlyHint and openWorldHint, indicating a safe, non-destructive operation. The description adds valuable behavioral details beyond the annotations: it explicitly states that requests are automatically narrowed to authorized bucket IDs when bucket-scoped, that results are truncated if exceeding the limit, and it describes the return fields (ID, name, type, CORS rules, lifecycle rules). This enhances transparency beyond what the annotations alone convey, though it does not fully describe edge cases like error handling.

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 moderately concise, but it is well-structured with two main sentences: one stating the core action and filters, another explaining the cap and truncation. It front-loads the primary purpose and includes necessary details without excessive verbosity. It could be slightly tightened (e.g., merging repeated 'filter' mentions), but it remains clear and efficient.

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 that there is no output schema, the description compensates by explicitly listing the returned fields (ID, name, type, CORS rules, lifecycle rules). It also covers important context such as the automatic authorization narrowing and the truncation behavior, which are essential for a user to understand the tool's behavior in a real-world B2 account scenario. The description is complete for the complexity of a simple list operation.

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?

The input schema already provides descriptions for all four parameters with 100% coverage, including default values and enums for bucketTypes. The description reinforces these by explaining the purpose of the limit (to keep response small) and the consequence of exceeding it (truncation with a note). This adds semantic value, particularly around the limit parameter, going slightly beyond the schema's own descriptions.

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 lists B2 buckets for the authorized account, using a specific verb ('List') and resource ('B2 buckets'). It distinguishes itself from other list tools by mentioning optional filters (by bucket ID, name, or type) and the automatic narrowing to authorized bucket IDs when bucket-scoped. This makes its purpose unambiguous and distinct from sibling tools.

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 provides context on when to use the tool: it is the primary listing operation, and it explains that the response is capped and how to handle truncation (raise the limit or add filters). While it does not explicitly mention alternative tools (e.g., b2_list_keys or s3_list_objects_v2), the context is clear enough for typical usage. It falls just short of explicit 'when-not-to-use' guidance, hence a 4.

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