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

Goes well beyond the annotations (which only declare it is not read-only, is open-world, and non-destructive) by disclosing that it does not ask for confirmation, that the client immediately sees the workout, that it can be edited/deleted afterward in TrueCoach, that it returns an ID, and that a scoped API key is required.

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-loads the action and resource, then layers in mechanics and caveats in short sentences. Slightly dense but every sentence carries distinct, actionable information.

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 mutation tool with no output schema, the description covers the key concerns: side effects (client visibility, no confirmation), reversibility (edit/delete in TrueCoach), return value (the workout ID), and auth (Cotlet API key). Only the lack of explicit alternative routing keeps it off a 5.

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 already 100%, so the baseline is 3, but the description adds genuine meaning: warmup/cooldown are free text, sets/reps/tempo/rest belong in the exercise description, and exercise names must come from the TrueCoach library. This clarifies how to populate the loosely-typed 'items' string.

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 ('Write a workout on a client's workout calendar for a given day') and clearly distinguishes itself from read siblings like get_workout/list_workouts and from assign_program. An agent can identify the operation without opening the schema.

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?

Implies usage (schedule a workout for a specific client and day) and gives one prerequisite (a Cotlet API key with app access), but offers no explicit when-not guidance or routing to alternatives such as assign_program for program-based scheduling.

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