client_session_stats

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

With no annotations, the description carries the full burden. It discloses the read-only nature ([READ]), platform-dependent error behavior, unbounded result set ('this listing is always complete'), and ordering ('busiest first'). It does not discuss permissions or rate limits, but for a read-only stats tool this is adequate.

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 well-structured with a clear [READ] tag, purpose statement, platform caveat, Args section, and Returns section. Every sentence conveys useful information, and the inline error example is compact yet prevents unnecessary retries.

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 listing tool with no output schema, the description adequately specifies the output shape (clients array, returned count, truncated flag), the unbounded nature, and the error case. It also notes the ordering and platform compatibility, making it complete for the tool's complexity.

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 only parameter 'target' is clearly explained as 'IdP target name from config; omit for the default.' With schema coverage at 0%, the description fully compensates by adding the semantic meaning and optionality that the input schema lacks.

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 'Active-session counts per client, busiest first (Keycloak)', which is a specific verb+resource plus the aggregation scope and ordering. It distinguishes from sibling tools like client_sessions by focusing on per-client rollup counts rather than individual sessions.

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 provides clear platform constraints: 'KEYCLOAK ONLY' and explains that authentik will return an error object and should not be retried. It gives a usable when-not-to-use and error-handling instruction, though it does not explicitly name alternative tools for the same use case.

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