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

Annotations only declare readOnlyHint=true, so the description carries the real behavioral burden and does so well: it explains the two shapes a plan can take, that a plan with `document` but no exercises/meals IS the coach's PDF, and that a null `document.text` means the PDF is scanned or unreadable — plus the remediation step for the coach. That is substantial context beyond the annotation.

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 what is returned, then the calling instruction, then the PDF edge cases. It is on the long side, but each clause (cardio fields, PDF-as-plan, null text remediation) conveys distinct, actionable information rather than filler.

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?

No output schema exists, so the description must describe returns — and it does, covering both the structured exercise fields and the document.text case. For a single-parameter read tool with a rich return shape, nothing an agent needs to call it correctly is 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 0% for the single parameter, so the description must compensate. It names the parameter's role and its source ('the plan _id from list_workout_plans'), which is genuinely useful, though it doesn't state the id's format or whether it can be a template id.

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 ('Full detail of one client workout plan') and enumerates what the detail includes (exercises with sets, reps, rest, section, notes, cardio fields, plus PDF text). This distinguishes it cleanly from list_workout_plans and get_workout_plan_template without opening either 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?

It tells the agent where the required id comes from ('Pass the plan _id from list_workout_plans'), which is the key routing fact. It stops short of explicitly contrasting with get_workout_plan_template or the update/delete siblings, so there is no stated when-not, but the retrieval context is unambiguous.

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