session_stats

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

Description mentions an optional parameter 'external_session_id' that does not exist in the schema (which has no parameters). This is a contradiction between description and schema. No information about side effects, permissions, or data returned.

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 brief but contains inaccurate information (referencing a non-existent parameter). Conciseness is undermined by the lack of accuracy.

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?

Without output schema or annotations, the description should clearly explain return values. It does not describe what the tool outputs (e.g., format, fields). The scoping hints provide some context but not enough for complete understanding.

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 has zero parameters, but the description claims an optional 'external_session_id' parameter. This misleading addition degrades the agent's ability to invoke the tool correctly. Schema coverage is 100% for an empty schema, but the description adds false semantics.

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?

Description states 'Token analytics' with three scopes (session, history, daily), suggesting it returns token usage statistics. However, it does not specify what metrics are returned (e.g., count, cost, etc.), making the purpose only moderately clear.

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?

No guidance on when to use this tool over siblings like set_external_session_id. No preconditions or exclusions are mentioned, leaving the agent to infer usage context.

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