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

Annotations already declare readOnlyHint, idempotentHint and destructiveHint=false, so the safety profile is covered; the description reinforces it with 'READ-ONLY: nothing is written or prescribed.' More valuably, it discloses the return shape (alert types DRUG/ALLERGEN/CONDITION, severities MINOR/MODERATE/MAJOR, description, involved medications), which no output schema provides.

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 core action and scope, then the read-only guarantee, then the return shape, then the API reference. Slightly redundant to restate the read-only hint that annotations already carry, but no sentence is wasted.

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?

With no output schema, the description usefully enumerates alert types and severities, and the API field name (prescriptionScreen) aids callers. Minor gaps remain: no note of the 20-item screening limit or guidance on what to do when no patient history exists.

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 patient_id, treatment_ids and diagnosis_codes are already fully documented in the schema. The description's mention of allergies/history/existing prescriptions is conceptual context rather than parameter-level detail, so the baseline 3 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?

States a precise verb (screen) and resource (proposed medications) and names the three interaction classes it checks: drug-drug, drug-allergy, and diagnosis. This is clearly distinguishable from the read/list/search siblings, which all operate on stored entities rather than evaluating a proposed regimen.

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?

Explains the inputs it draws on (patient allergies, medication history, existing prescriptions) and that it evaluates 'proposed' treatments, which tells the agent this is a pre-prescription check. It stops short of explicitly naming conditions for preferring this over siblings or stating when not to use it.

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