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

Annotations already declare readOnlyHint=true and destructiveHint=false, so safety is covered. The description adds genuinely useful behavioral context beyond that: the library size (1000+) and the fact that unfiltered calls are wasteful. It still omits return-format/pagination detail, but that gap is minor for a read-only list tool.

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?

It is front-loaded with the core purpose in the first sentence and then layers the filtering imperative. The repeated emphasis on filtering is slightly redundant but each sentence carries distinct guidance (filter rule, multi-call workflow, clarifying question).

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 read-only catalog tool with a fully documented schema and no output schema, the description covers usage conditions, filtering expectations, and the disambiguation step. It leaves minor gaps around return shape and default behavior, but nothing essential for correct invocation.

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% with enums on muscle, category and equipment, so the schema already carries the load. The description only adds illustrative usage (muscle="chest" for push, muscle="quads" for legs) rather than new syntax or format semantics. Baseline 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?

The description opens with a specific verb and resource: "Get exercises from the library." The word "library" implicitly separates it from siblings like get_exercise_records (the user's logged history) or get_personal_records, but it never explicitly names a sibling to disambiguate.

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 states a hard when-to-use rule ("ALWAYS filter before calling — never fetch without at least one filter"), a workflow context ("Before building a routine, call this multiple times"), and a prerequisite ("If you do not know what muscles/equipment the user wants, ask them first"). When-not and prerequisite conditions are both explicit.

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