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

Annotations only give readOnly=false/destructive=false/openWorld=false, but the description discloses the actual behavior: it validates the workout, matches exercises to the movement library with demo links, flags equipment/time violations, stores a private 24-hour preview, and explicitly does not save training to an account. The 24-hour retention and 'ask before saving' flow are behavioral facts the annotations cannot convey.

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 use case before capabilities and constraints, and every sentence carries distinct information (trigger, behavior, side effect, downstream step, exclusions). It runs five sentences and is slightly dense, but there is little waste.

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 not be described. Given the complex nested workout schema, single-param requiredness, and the mutation-adjacent 24-hour preview, the description supplies the trigger, side effects, warning-handling expectation, and exclusions needed to call it correctly.

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%, so the schema documents all four params, setting a baseline of 3. The description adds meaning by explaining why time_limit_minutes and available_equipment matter (they drive the runs-past-time and equipment-not-listed warnings) and how origin ties to preview_sport_week, exceeding the schema's own text.

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/check) and resource (a single workout to follow and track in Phorme) and enumerates the accepted origins (written in conversation, pasted from notes, built to fit time/equipment). It clearly distinguishes itself from program-scale and other sibling tools by scoping to 'a single workout'.

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 when-to-use trigger, names the downstream alternative (save_workout_to_phorme) and the origin link to preview_sport_week, and closes with explicit exclusions ('Do not use it for multiweek programs, nutrition plans, or pain and injury questions'). Routing is unambiguous.

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