get_mobile_analytics

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

Annotations only cover safety (readOnly/idempotent/openWorld); the description adds the critical behavioral fact that the call fails rather than returning invented numbers. This is exactly the kind of disclosure an agent needs to avoid trusting phantom data, and nothing contradicts the annotations.

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?

Two tight sentences, with the decisive 'UNSUPPORTED' status front-loaded. Every word earns its place with no filler.

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?

For a stub tool with no output schema, the description fully explains why no data is returned and what the caller gets instead. Complete enough to prevent misuse, though it could note whether the error is unconditional.

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% with a single 'days' parameter fully described in the schema. The description adds no parameter-specific meaning beyond the schema, so the baseline 3 applies.

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 plainly that the tool is unsupported and returns an error instead of fabricated counts. The verb/resource ('get mobile analytics') is implicit in the name, and the description makes the actual behavior unmistakable, though it doesn't explicitly contrast with sibling tools like get_mobile_app_config.

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?

It signals strongly that this tool should not be relied on for real data ('returns an error'), which is useful usage guidance. However, it doesn't direct the agent to any alternative source or say under what conditions the tool would become usable, leaving the 'what to do instead' question open.

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