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

With no annotations, the description carries the full burden and does well: it discloses the result volume ('up to a handful of boats'), the price nature ('indicative weekly'), and — importantly — the quota/authentication model (first search free, then 4/day via verified email or 10/day via phone, pointing at verify_email/verify_phone). It omits pagination, ranking logic, and whether empty results are possible, which prevents a 5.

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?

Four short sentences, front-loaded with purpose, then parameter strategy, then return shape, then cost/auth constraints. No sentence is redundant and no information is buried.

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?

For a 13-parameter, nested-object search with no output schema and no annotations, the description covers the return shape at a high level and the quota model that materially affects how the agent should call it. What is missing is how filters combine (AND semantics), ranking of the 'handful' of results, and what to do on zero results — minor but real gaps for a tool of this complexity.

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% with per-field descriptions and three enums, so the schema does the heavy lifting and the baseline applies. The description adds only the useful meta-fact that nothing is required and filters should be filled from what the client said; it contributes no per-parameter meaning beyond that.

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 ('Find charter yachts') and frames the input as a client brief, so the agent knows this is a discovery/search tool. It does not name sibling tools like yacht_details or check_availability to delimit the boundary, leaving the agent to infer that this is the entry point and the others are follow-ups.

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?

'All fields are optional; pass what the client has told you' gives clear progressive-filling guidance for invocation. However, there is no explicit when-to-use versus the siblings (e.g. call yacht_details for a single boat, check_availability for dates), so the routing signal is only implied.

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