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

With no annotations, the description carries the full behavioral burden. It does useful work by disclosing the return shape (datetime, height in meters, high/low type) and dataset breadth (18,400+ stations), but says nothing about station-matching behavior for lat/lon, what happens if both port and coordinates are supplied, rate limits, or error handling for out-of-range inputs.

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?

Three short sentences: purpose first, return values second, coverage last. No filler, and the most important information is front-loaded.

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?

No output schema exists, and the description compensates by describing the returned extremes and units. For a six-parameter read tool with all-optional parameters, the remaining gap is mainly the port-vs-coordinates precedence and station resolution behavior.

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 all six parameters (including the datum enum and 1-14 day cap) are already documented in the schema. The description only restates that port and coordinates are the two location modes, adding no format or precedence detail 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?

States a specific verb and resource ('Get tide predictions') plus the unit of return ('high/low water times and heights') for either a port or coordinates. It clearly separates from get_astronomy/get_weather by naming tides, but never explicitly contrasts with the closest sibling get_marine, which may also touch tidal data.

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 by the purpose: call this when you need tide extremes. There is no explicit when-to-use/when-not guidance, no mention that search_ports should be called first to resolve a slug, and no contrast with get_marine or get_astronomy.

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