sessions_list

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

No annotations are provided, so the description carries the full burden of behavioral disclosure. It usefully reveals that the tool uses S3 CommonPrefixes with Delimiter='/', which means it only lists immediate prefixes and matches the behavior of 'aws s3 ls'. However, it does not disclose pagination behavior, output format, or whether any filtering is applied beyond the prefix.

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 with no filler. The primary purpose is front-loaded, and the second sentence adds a valuable implementation clarifier. Every word earns its place.

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 covers the core behavior sufficiently for a simple listing operation: it states the target path and the type of items returned. However, with no annotations and no output schema, it omits details about pagination and response structure. The tool is simple, but the same could be said of analogous list tools that still explain continuation tokens.

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% for parameters, so the description is expected to compensate. It does not mention 'limit' or 'continuation_token' at all, nor does it explain their meaning or interaction. The parameter names and defaults are self-evident, but no semantic enrichment is provided.

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 a clear verb-resource pair: 'List session IDs (prefixes) under sessions/.' It clarifies the tool returns prefixes, not full objects or other entity types. However, it does not explicitly contrast itself with sibling tools such as sessions_list_messages or sessions_list_agents, so it falls just short of perfect differentiation.

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?

There is no guidance on when to use this tool versus alternatives. The description provides an implementation analogy to 'aws s3 ls' but never says when this tool is preferred or when another sibling should be chosen. Usage context is only barely implied by the action word 'List'.

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