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

Annotations already set readOnlyHint and openWorldHint; description adds valuable behavioral context: blank/out-of-service signs filtered, 2-minute cache, and that data reflects road truths before other sources. No contradiction.

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?

Compact yet information-dense, organized into clear sections (Data, Refresh, Filters, Usage). Every sentence serves a purpose with no fluff.

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?

Fully explains data content, refresh cadence, and filtering parameters. Without output schema, it describes what users get (sign text). Could mention typical response size or pagination, but sufficient for the tool's simplicity.

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?

With 0% schema description coverage, description fully compensates by explaining all three parameters: route (e.g., 'I-80'), center 'lat,lon', and radius_km with default value. Adds examples and usage context.

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?

Description clearly states the tool returns 'what Caltrans changeable message signs are displaying right now,' distinguishing it from siblings by emphasizing real-time operational truth before other feeds.

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?

Provides clear usage guidance: 'Quote sign text verbatim to the user - it is the most current and most local signal.' Implicitly contrasts with other feeds but does not explicitly list when not to use or name specific alternatives.

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