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

Annotations already declare read-only, idempotent, non-destructive behavior. The description adds valuable non-obvious guidance: when a session has a local_date, quote it rather than converting the UTC date field. This goes beyond structured annotations and helps the agent use results correctly.

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 tightly written and front-loaded. Each sentence earns its place: purpose, output content, a concrete use case, and an important date-handling instruction. No filler or repetition of schema details.

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?

The tool is simple, the input schema fully documents parameters, annotations cover safety, an output schema exists, and the description adds the one behavioral subtlety (local_date handling). This is complete enough for an agent to invoke the tool correctly.

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 100%, with both exercise_name and limit already described in the input schema. The description provides no additional parameter-level detail, so the baseline of 3 applies.

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 opens with a specific verb and resource: 'Get performance history for a specific exercise across sessions.' It also enumerates the returned content (sets, volume, estimated 1RM, heaviest set, trends), making the tool's purpose unmistakable and distinct from sibling tools like get_training_maxes or get_workout_detail.

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?

It gives a clear usage context: 'most useful tool for coaching conversations like How's my bench progressing?' This tells an agent when to reach for it. It does not explicitly name alternatives or exclusion conditions, so it stops short of a 5.

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