get_session_stats

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

The readOnlyHint annotation already signals a safe read operation. The description adds context that the statistics are cumulative across all tool calls, which clarifies the aggregation behavior beyond the annotation. No other behavioral traits (e.g., calculation method) are disclosed, but the simple read-only nature reduces the need.

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, concise sentence that front-loads the key information without any filler words.

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 fully explains the tool's return value and scope (cumulative across all tool calls) for a simple zero-parameter read-only tool. No output schema exists, but the description sufficiently describes the return in terms of token savings and cost avoided.

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 accepts no parameters, so the description correctly adds no parameter details. With zero parameters, the schema coverage is trivially 100% and the baseline is 4.

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 tool returns cumulative token savings and cost avoided across all tool calls, using a specific verb and resource. This distinguishes it from the sibling tools, which focus on data operations rather than session-level statistics.

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 is given on when to use this tool versus alternatives, and no alternatives or exclusion conditions are mentioned. The description implies it is for retrieving overall session statistics but does not specify a clear use case context.

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