list_objects

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

Annotations already declare readOnlyHint=true, so the read-only nature is covered. The description adds useful behavioral details: it returns a single page, respects max_keys, includes key/size/last_modified fields, and provides a truncated flag when more results exist. This goes beyond the annotation and clarifies pagination behavior without contradicting it.

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 concise sentences, with the primary purpose front-loaded. The pagination detail and return fields are stated without redundancy. Every clause earns its place; there is no fluff or unnecessary explanation.

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 tool is relatively simple (3 params, output schema present), and the description covers the main behavior and return fields. However, the prefix parameter is entirely unmentioned, which is a significant gap for filtering results. An agent would not know that prefix is available for narrowing the listing, making the description incomplete for full usage.

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 0%, so the description must compensate. It explicitly mentions max_keys and implies bucket, but entirely omits the prefix parameter. Since prefix is a common filtering mechanism, the description fails to explain its purpose or usage, leaving agents without guidance for that parameter. The description adds partial value for max_keys but is incomplete.

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 states 'List objects in a bucket' with a specific verb and resource, and distinguishes itself from siblings like list_buckets (which lists buckets) and get_object (which retrieves a single object). It also adds the key constraint 'single page, up to max_keys' which further differentiates its behavior.

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 implies when to use the tool (to list objects) but does not explicitly contrast it with alternatives. It does not mention that get_object or stat_object should be used for single-object needs, nor does it state when not to use this tool. The pagination hint (truncated flag) provides context, but no explicit exclusions or sibling routing.

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