session_stats

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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, so the safety profile is well covered by structured data. The description adds the output nature (aggregate statistics) but does not disclose additional behavioral details such as data freshness, scoping semantics, or failure conditions, which is acceptable given the annotation coverage.

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 compact sentences with no filler. The [READ] marker and primary summary are front-loaded, and the sibling contrast is placed in the second sentence, making the essential information immediately visible.

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?

For a read-only tool with one optional parameter and no output schema, the description adequately lists the return categories (concurrency by state/protocol, current concurrent, busiest pools). It does not specify the exact output structure, but the listed categories give an agent sufficient expectations for a straightforward stats call.

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 100%, and the single optional target parameter is fully described with a default and usage guidance. The tool description adds no parameter-level detail, but the schema already carries that burden, so the baseline score of 3 applies.

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 exactly what the tool provides: session statistics covering concurrency by state/protocol, current concurrent count, and busiest pools. It further distinguishes itself from session_list by clarifying it returns aggregate numbers, not per-session rows, making its purpose unmistakable.

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 names session_list as the reporting counterpart and contrasts aggregate numbers with per-session rows, giving an agent a clear decision point. It does not cover when to use other reporting siblings like pool_utilization or health_summary, so it is clear but not exhaustive.

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