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

With no annotations, the description carries the full burden. It usefully discloses replacement semantics ('sends every field') and confirm-gating, which is real behavioral context. However, it omits permission/auth requirements and what happens to omitted optional fields (e.g., locationId, instructorCoachId) — whether they are cleared or retained — which matters for a PUT-style mutation.

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 tightly-packed sentences with the destructive replace semantics front-loaded and the prerequisite trailing. Every clause earns its place, no filler.

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 an 11-parameter (6 required) mutation tool with no annotations, no output schema, and only 36% schema coverage, the description is somewhat sparse. The replace-plus-confirm framing is appropriate, but behavior around optional fields and permissions is left unspecified.

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 low at 36%, so the description should compensate. It adds the critical semantic that every field must be sent (full replace), implying the agent must fetch current values via list_gym_classes. But it documents no individual parameters, leaving most of the 11 params to the sparse 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 verb ('Replace') and resource ('a recurring class's definition'), immediately distinguishing it from sibling create_gym_class by signaling full-replacement semantics. The scope is clear enough that an agent can select it correctly, though it doesn't explicitly contrast with deactivate_gym_class or other update options.

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?

Provides a concrete prerequisite: 'read list_gym_classes first,' which gives the agent the correct call sequence for a full-replacement update. It also flags the confirm-gated behavior. It stops short of stating when-not-to-use or naming alternative mutation siblings, so it's clear context rather than full when/when-not routing.

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