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 and the description goes further by disclosing data behavior: results are grouped as in the Metric Manager, ordered newest first, and metrics linked to a workout exercise update when the client logs a result. It also notes the Cotlet API key requirement. Pagination behavior is not disclosed.

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 resource and what is returned, followed by behavioral notes. Sentences are informative and mostly earn their place, though the leading "TrueCoach:" prefix is slightly redundant against the title and costs a little space.

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, single-parameter list tool with annotations covering the safety profile, the description is largely complete. It compensates for the missing output schema by describing the return shape (values with dates, grouped, newest first). Only pagination/size limits are left unaddressed.

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% and the single client_id parameter is fully documented ("Client ID from list_clients"). The description adds no syntax or sourcing detail beyond the schema, so the baseline 3 for schema-documented parameters 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 uses a specific verb ("Returns") on a precise resource ("a client's metrics ... with their values over time") and gives concrete examples (back squat, body fat %). An agent can immediately tell this is a read operation returning metric history. It does not need to differentiate from a competing list tool, but it also doesn't explicitly name the related write sibling truecoach_update_metric.

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?

Usage is implied by the verb "Returns the metrics assigned to the client," so an agent understands this fetches metric history for a given client. However, there is no explicit when-to-use/when-not guidance and no mention of alternatives such as truecoach_get_client or truecoach_update_metric to route between read and write paths.

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