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

Annotations only declare readOnly=false, idempotent=false, destructive=false; the description goes well beyond that with the idempotency key mechanics, the superset adjacency constraint and pointer to the field rule, and the fact that strength and conditioning exercises can be mixed and are measured by their own exercise_type. This is behaviorally rich, non-duplicative context for a mutation 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?

Front-loaded with the purpose, then a sequence of one-rule-per-sentence statements that all earn their place (idempotency, superset rule, type mixing). It is dense rather than padded, though a few points repeat schema text verbatim and could have been trimmed.

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?

With an output schema present, the description correctly avoids explaining return values and instead covers the things structured data cannot: idempotent retry behavior, superset grouping constraints, mixed-modality workouts, and unit/type expectations. Nothing an agent needs to invoke this correctly appears to be 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 coverage is 100%, so the baseline is 3; the description nonetheless adds cross-field semantics the schema states only per-field — e.g. that each exercise carries its own exercise_type and that only the targets that type accepts should be sent, and that superset membership is governed by the superset_group rule. Some of its parameter content (exercise_id provenance, superset labels) duplicates what the schema already says, keeping it below a 5.

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 and resource with scope: "Schedules a planned workout in the app on a chosen date." It also names the required upstream tools (search_exercises, create_custom_exercise) for exercise_id, which helps an agent locate the tool in a workflow. It does not explicitly distinguish itself from update_planned_workout or list_planned_workouts, so it stops short of full sibling differentiation.

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 concrete preconditions and alternatives: exercise_id must come from search_exercises or create_custom_exercise and never be invented, and it explains the retry policy (reuse the same client_request_id rather than blindly retrying). It does not state when to prefer update_planned_workout over creating a new session, which is the one obvious sibling decision left unaddressed.

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