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

Annotations already declare readOnlyHint=true, openWorldHint=false and destructiveHint=false, so the safety profile is covered. The description adds the returned field list, which is genuinely useful context, but says nothing about pagination, ordering, or how 'recent' is bounded beyond the schema's period/limit defaults.

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?

A single tight sentence with no filler and no redundancy. It is marginally less front-loaded than ideal since it enumerates outputs rather than leading with the action, but nothing is wasted.

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 10-parameter list tool with no output schema, the field enumeration partially compensates for the missing return documentation, and the schema covers most parameters. Still missing is routing guidance versus get_session and any note on ordering or result volume, leaving clear gaps.

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 90%, with defaults, ranges and filter grammar already documented in the schema, so the schema does the heavy lifting. The description contributes no parameter meaning beyond what is structured, making baseline 3 appropriate.

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 name plus the phrase 'Recent sessions with entry/exit page, pages viewed, duration, source, location and device' makes clear this returns a list of sessions and enumerates the fields returned. However, it never distinguishes itself from the singular sibling get_session, so an agent must infer whether to use list vs get.

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?

There is no statement of when to use this tool, no prerequisites, and no mention of adjacent alternatives such as get_session, get_journeys, or get_realtime. The agent gets the what but not the when.

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