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

Annotations already declare readOnlyHint=true and openWorldHint=false, so safety is covered. The description does add real value with the 'up to 14 days' range cap and the fact that each slot carries a booking_url, but it is silent on what happens if the range exceeds 14 days (error vs truncation), what an empty result means, and how pricing is expressed.

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?

A single dense sentence with the core payload (start times, prices, booking_url) front-loaded and the 14-day scope attached. Nothing is wasted, though the sentence compresses several distinct facts into one clause chain.

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 does sketch the return shape (start times, prices, booking URLs), which is the right instinct. For a 4-parameter read tool it is still thin on edge behavior — empty results, range overflow past 14 days, and how duration filters slots are all unaddressed.

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 75%, so date_from, date_to, and duration are already documented in the schema. The description's phrase 'for one field' usefully clarifies that field_id selects a single field rather than a set, but it says nothing about duration, which materially changes which start times are returned.

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 description names a specific resource and return payload: open start times with prices for one field, each with a booking_url. It is clearly distinct from get_field and search_fields, which operate on field records rather than availability, though it never states that contrast explicitly.

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?

Usage is only implied — an agent can infer this is the tool for checking open slots for a known field over a date range. There is no explicit 'use this when...' guidance, no note that a field_id must be obtained first (e.g. via search_fields), and no exclusions.

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