Apple Maps insights

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

Even though annotations already declare readOnlyHint: true, the description adds substantial behavioral context: how comparisons affect metrics (comparison fields with prior, delta, deltaPercent), detailed error handling for rate limits and not-found cases, and guidance to check structuredContent.errorCode and retryable. This goes well beyond the annotation.

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 well-structured with clear sections: main purpose first, then comparison options, then error handling. It uses bullet points without excessive length, and every sentence provides distinct value. No redundancy or 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?

Given the tool's complexity (6 params), the presence of an output schema, and read-only annotation, the description is remarkably complete. It covers error handling, comparison behavior, and aggregation defaults, while leaving return-value details to the schema. This is sufficient for an agent to select and invoke the tool correctly.

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 the baseline is 3. The description adds value by explaining comparison semantics (MoM, QoQ, YoY) and the behavior when comparison is active. It also clarifies the 'total' aggregation's token-reduction benefit. This extra context justifies a 4.

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 opens with a specific verb+resource statement: 'Fetch Apple metrics for all locations, or a single location if storeId provided.' This clearly identifies the tool's function and scope, and the 'Apple' qualifier distinguishes it from sibling Google/Facebook insights tools.

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 provides clear context for use—fetching Apple metrics with optional storeId, aggregation, and comparison. However, it does not explicitly state when not to use it or name alternatives. The sibling distinction is implied by 'Apple metrics' but not stated as an exclusion.

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