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

readOnlyHint=true already covers the safety profile, but the description adds nothing about behavior: 'last-week' is undefined (calendar week vs rolling 7 days), and it doesn't say what happens when the client has no record for that exercise. For a stats read whose whole value hinges on the time window, this is a meaningful omission.

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 front-loaded sentence with no filler. It is efficient, though its brevity shades into under-specification rather than crispness.

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?

No output schema, no annotations beyond readOnlyHint, and an undocumented required parameter mean the description should carry more weight than one clause. The ambiguous time window and the empty-result behavior are the two things an agent would need and neither is present.

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 coverage is only 50%: clientId documents its source (list_clients), but exerciseName has no description. The description does not compensate — it never says whether exerciseName must be an exact catalog match or whether the agent should call search_exercises first, which is the main failure mode for this tool.

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 names the resource and the exact metrics returned (personal record, average, last-week weight) scoped to a single exercise, which is far more specific than the tool name alone. It stops short of contrasting with neighbors like get_exercise_history or get_client_personal_bests, so the agent must infer why it would pick this over those.

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 guidance on when to use this versus get_exercise_history, get_client_personal_bests, or get_client_progress, all of which plausibly overlap. No prerequisites (e.g. resolving exercise names via search_exercises) are mentioned.

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