session_stats

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

No annotations are provided, so the description carries the full burden. The term 'stats' strongly implies a read-only query operation, and the description discloses the kind of data returned (totals, most-used tools, most-analyzed targets). However, it does not explicitly state that no modifications are made, nor does it hint at performance implications.

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 a single sentence that front-loads the core purpose ('Global MCO stats') and then lists the specific metrics. It is succinct, with no wasted words, and each metric adds value.

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 zero-parameter tool with no output schema, the description adequately conveys the high-level content of the results. It could be more explicit about the exact return format or how it differs from session_summary, but given its simplicity, it is largely complete.

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 tool has zero parameters and an empty input schema, leaving no parameter semantics to explain. With 0 params, the baseline is 4, and the description correctly says nothing about parameters.

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 identifies the tool as providing 'Global MCO stats' and enumerates specific aggregates: 'total sessions, total tool calls, most used tools, most analyzed targets.' It distinguishes itself from sibling session_* tools by emphasizing 'Global' scope.

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 word 'Global' implies use for cross-session overview, but the description does not explicitly state when to use this tool instead of session_summary or other session-specific tools. No alternatives or exclusions are mentioned, leaving usage guidance implied rather than explicit.

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