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

Annotations already declare readOnlyHint, idempotentHint and destructiveHint=false, so the bar is lower. The description adds the non-obvious behavioral constraint that the payload must be the verbatim structuredContent from another tool rather than fabricated data, which is genuinely useful. It stops short of describing rendering side effects or failure modes when the payload is malformed.

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, zero filler, with the purpose front-loaded and the dependency instruction immediately after. Everything earns its place.

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?

An output schema exists so return values need no explanation, annotations cover the safety profile, and the one parameter plus its required provenance are both documented. Nothing an agent needs to call this correctly is missing.

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% and the schema already says 'Pass it through unchanged', so the baseline would be 3. The description adds value by telling the agent where the payload must come from (get_destination_weather's structuredContent), which the schema does not state, resolving the provenance of the opaque nested object.

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+resource ('Render the destination weather card') and is easily distinguished from the sibling get_destination_weather (fetch) and render_destination_info (different card). An agent can pick it out of the sibling list without opening the schema.

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?

Gives an explicit prerequisite and sequencing rule ('Always call get_destination_weather first, then pass its structuredContent here') plus an exclusions rule ('Do not invent weather data'), naming the sibling that supplies the data. This is about as prescriptive as a rendering tool can be.

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