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

Annotations already declare readOnly, idempotent, non-destructive, and openWorld, so the description's restatement of 'strictly read-only, zero state mutation' is redundant. It does add genuinely new operational context: unauthenticated public access and a 60 requests/min per-IP rate limit, both of which an agent cannot infer from annotations.

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?

The first sentence is well front-loaded and informative. The remaining text is padded with a templated self-reference ('when you specifically need to execute...'), a generic returns sentence ('status, matched records or computed metrics'), and redundant read-only restatement that crowds out useful content.

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 one optional parameter, full annotation coverage, and no output schema, the definition covers what the agent needs: what the data contains, access constraints, rate limits, and that a JSON response with URLs comes back. The return description is vague ('matched records or computed metrics'), but nothing essential for calling the tool 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 100% and the single optional enum parameter is fully documented there, including the default of 'all'. The description only restates 'package_type (optional)' without explaining what the gender/4d/2d/heartbeat categories mean or how they change results, so it adds no value beyond the schema.

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 opening sentence gives a specific verb ('Retrieve') plus concrete resources: ultrasound packages, scan durations, ZAR prices, and inclusions like thermal prints and heartbeat recordings. It is clearly differentiated from siblings in kind (pricing/packages vs. booking or studio info), though the sibling differentiation is delivered through a boilerplate template rather than real domain distinctions.

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 provides an explicit do-not-use clause naming get_studio_info, get_gestational_guide, and check_booking_availability, which is better than nothing. However the positive 'when to use' guidance is circular ('when you specifically need to execute get_scan_packages_and_pricing'), and the alternatives are listed without saying which conditions actually select them.

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