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

The description adds significant behavioral context beyond the annotations, such as that it 'returns concrete owner + sessionId pairs', 'supports keyset pagination', and gives a specific usage hint for time windows. Annotations already indicate read-only and idempotent behavior, and the description reinforces and expands on this without contradiction.

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 sentences long, with the first clearly stating purpose and when to use, and the second adding key operational details. Every sentence is informative and free of fluff. It is well-structured and front-loaded.

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 an output schema (not shown but indicated by context signals) and annotations cover safety, the description is quite complete for a listing tool. It explains the return type (owner+sessionId pairs) and pagination. However, it could briefly mention the overall list-like return structure, but the output schema fills that gap.

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 coverage is 100%, so the schema already documents all parameters. The description adds only one example usage ('For “last 3 weeks”, pass windowHours=504') and mentions keyset pagination, which relates to the 'cursor' parameter. This adds marginal value but does not significantly enhance understanding beyond the schema.

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 verb 'list', the resource 'XDaLa sessions', and the specific return of 'concrete owner + sessionId pairs' with keyset pagination. It also differentiates from siblings like 'list_xdala_session_ids' and 'get_recent_xdala_sessions' by specifying the exact output and pagination support.

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 tells when to use the tool (e.g., 'when the user asks to list XDaLa sessions') and provides a concrete example ('For “last 3 weeks”, pass windowHours=504'). However, it does not explicitly state when not to use it or suggest alternatives, leaving some room for ambiguity.

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