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

Beyond the annotations (readOnly, openWorld, non-destructive), the description discloses anonymous rate limits (60/hour, 300/day per IP and session), that no API key is required with anonymous fallback after quota, that geometry is omitted from returns, that hydrological units are normalised to SI, and that source licence warnings apply. This is substantial operational context the annotations do not carry.

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 purpose is correctly front-loaded, but the description is dense with boilerplate that does not aid tool selection: 'TerraMCP is a Wrench AI service', quota fallback mechanics, and licence-warning phrasing consume space. It is not wasteful enough to be a 2, but several sentences do not earn their place in a selection-time description.

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 sketches the return shape (bounded attributes, no full geometry, source data and provenance) and notes SI normalisation and result limits. Combined with rich annotations and a fully documented schema, an agent has enough to invoke it correctly; only the precise attribute set returned is left unstated.

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%, so each of the five parameters is already documented, and the description largely restates that (WGS84, bounding-box behaviour, bounded result set). The only mild addition is framing the search as a 'small' bounding box, which does not materially extend the schema's meaning. Baseline 3 is appropriate.

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?

Names a specific verb (Query) and four concrete resources (Main Rivers, Recorded Flood Outlines, Flood Warning Areas, Spatial Flood Defences) scoped to a WGS84 bounding box. It also implicitly separates itself from the flood-warning siblings by stating the data are 'not live warnings or a site-specific flood risk determination', so an agent can distinguish it from flood_list_warnings and flood_zone_at_point.

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?

The exclusion clause ('Historical/administrative datasets are not live warnings') tells the agent when this tool is the wrong choice and implies the warning siblings are the right ones. However, no alternative tool is named explicitly, so the routing guidance is contextual rather than prescriptive.

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