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

Annotations already declare readOnly/idempotent/non-destructive, so safety is covered. The description adds genuinely new behavioral context beyond the annotations: the Monday–Sunday week boundary and the is_partial=true flag for the in-progress week, which the agent could not infer otherwise.

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?

Front-loads the usage trigger, then packs the offset semantics and return fields into one tight sentence. The field enumeration is partly redundant with the output schema, which is the only mild waste.

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 single-parameter, read-only summary tool with an output schema covering return values, this covers when to use it, what the parameter means, and the one non-obvious behavior (partial current week). Nothing an agent needs to invoke it correctly is missing.

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 0%, so the description must carry the parameter. It does: 'week_offset 0 = this week, -1 = last week' gives direction and sign convention, enough to call the tool correctly without opening the schema.

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 retrieval: totals for one Monday–Sunday week, and enumerates the exact aggregates returned (workouts_count, total_volume_kg, total_duration_seconds, muscle_distribution). The weekly granularity inherently separates it from siblings like get_stats_overview and get_workout_history.

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?

Gives an explicit trigger with a concrete user utterance ('how was last week?'), which tells the agent exactly when to reach for this tool. It stops short of naming when NOT to use it or pointing at an alternative like get_stats_overview.

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