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

Annotations already declare readOnlyHint=true, openWorldHint=true, idempotentHint=true, and destructiveHint=false, so the safety profile is fully covered. The description adds meaningful behavioral context beyond annotations: it specifies the data source (api.weather.gc.ca MSC GeoMet OGC API - Features), states that no authentication is required, and clarifies that the tool returns observations for a station identified by CLIMATE_IDENTIFIER. It does not describe pagination or the output format, but the output schema exists and the annotations carry the safety burden, so this is a strong score.

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 description is a single, information-dense sentence that front-loads the core action and resource, then lists the returned variables, the required key, the optional date range, and the data source. Every clause earns its place, and there is no redundant repetition of schema or annotation content.

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?

Given the tool's moderate complexity (4 params, 1 required, output schema present) and the rich annotations, the description is nearly complete. It covers the data source, auth requirements, the station-ID prerequisite, and the optional date-range scoping. It does not mention pagination behavior or the default limit of 30 records, but the schema documents the limit parameter and the output schema exists, so the missing context is minor.

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 the schema already documents all four parameters. The description adds value by explaining the relationship between climate_identifier and the sibling tool msc-geomet.climate_stations, and by clarifying that start_date/end_date are an optional scoping pair. It also gives a concrete example of a CLIMATE_IDENTIFIER ('6158731' for Toronto Intl A), which helps an agent understand the expected format. The only minor gap is that the description doesn't explain the limit parameter's semantics beyond the schema, but the schema already covers 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?

The description states a specific verb ('Get'), a precise resource ('daily climate observations'), enumerates the exact variables returned, and identifies the required key (CLIMATE_IDENTIFIER) plus the optional date-range scoping. It also names the source API and the sibling tool that supplies station IDs, which distinguishes it from other climate/weather tools in the catalog.

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 description clearly indicates when to use this tool: to retrieve daily climate observations for a Canadian station by CLIMATE_IDENTIFIER, optionally within a date range. It references msc-geomet.climate_stations as the source for station IDs, which is a useful prerequisite. It does not explicitly state when not to use it or name alternatives (e.g., msc-geomet.aqhi.observations or meteostat.observations.daily), but the context is clear enough for an agent to select it correctly.

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