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

Annotations already cover the read-only, idempotent, non-destructive profile, and the description adds genuinely non-obvious context: the data are real drift bottles simulated on real currents every 3 hours, and privacy is guaranteed (never the note, name, or exact spot). It also flags that a spoken one-sentence summary is included, which shapes how the result should be used.

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 domain and key promise are front-loaded, and the enumeration of return fields is dense rather than padded. The opening clause about 'earlier versions of our free apps' is promotional filler that does not help an agent decide or call.

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 the returned fields and privacy limits, so the agent knows the result shape. The remaining gap is the all-optional parameter set: nothing says what is returned when called with no arguments, or how place overrides lat/lon.

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%, so lat, lon, limit, miles, and place are all documented in the schema itself. The description adds no parameter-level detail — notably it never explains the place-vs-lat/lon tradeoff that matters when none of the five parameters are required. 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?

The description names the resource and the concrete question it answers ('any bottles washed up near me?'), then lists exactly what comes back (counts, miles away, longest drift, days at sea). That is enough for an agent to know what it retrieves, though the framing is narrative and it never contrasts itself with any sibling tool.

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 through the quoted user question, which suggests 'call this when someone asks about bottles near a location.' There is no explicit when-not, no statement about what happens with zero parameters, and no routing to an alternative for related beach lookups.

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