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

Annotations only say readOnlyHint=false and destructiveHint=false, which leaves the write semantics ambiguous. The description resolves this: it stores a private 24-hour preview, does not persist to any account, and performs exercise-library matching — exactly the behavioral traits an agent needs before invoking.

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?

Four short sentences, each load-bearing: trigger, mechanics, persistence guarantee, exclusions. The most decision-relevant information (what it does and what it does not save) is front-loaded.

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?

An output schema exists, so return values need no explanation. For a complex nested-input tool with annotations covering only safety hints, the description supplies the missing lifecycle, persistence, and routing context.

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 one deeply nested, well-annotated parameter, so the schema already carries the parameter burden. The description adds only the provenance constraint that the program comes from the current conversation; no field-level meaning is added. Baseline 3.

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 (preview) and resource (a multiweek training program from this conversation) and describes the concrete steps taken: checking every week and workout, matching exercises to the Phorme movement library. It explicitly excludes single workouts, cleanly separating it from the sibling preview_workout_import.

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?

Opens with an explicit trigger ("Use this when the user wants to turn a multiweek training program... into trackable Phorme training") and closes with explicit exclusions ("Do not use it for a single workout, nutrition plans or medical questions"). The alternative for the single-workout case is named by implication.

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