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

Annotations already declare readOnlyHint=true, destructiveHint=false and openWorldHint=false, so the safety profile is covered without description help. The description adds value by disclosing the shape of the response (session type, exercises, duration, RPE, date), which is meaningful given there is no output schema, but it says nothing about ordering, recency window, or pagination behavior beyond what the schema already states.

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?

Two sentences, zero filler: the first states what is returned, the second states why it is useful. The resource and payload are front-loaded before the rationale.

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?

With no output schema, the description usefully compensates by listing the returned fields, and the annotations cover the read-only safety profile for a zero-required-parameter tool. The remaining gap is operational detail — default ordering and what 'recent' means in practice — which is minor but not fully closed.

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% — both 'limit' (default 30, max 100) and 'category' (enum of five values) are fully documented in the schema. The description adds no parameter-level detail, so the baseline of 3 is 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?

States a specific verb and resource ('Get the user's recent workout sessions') and enumerates the returned fields, so the agent knows exactly what this retrieves. It does not, however, distinguish itself from adjacent siblings such as get_session_details or get_workout_stats, which an agent could easily confuse with it.

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 second sentence gives an implied purpose ('understand training patterns, volume, frequency, and muscle group balance'), which signals when the tool is useful. There is no explicit when-not guidance and no named alternative (e.g. use get_session_details for a single session, get_workout_stats for aggregates), so the agent must infer the boundary.

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