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

Annotations already declare readOnly, idempotent, openWorld, non-destructive, so the safety profile is covered. The description adds genuinely useful context beyond annotations: results come back in store ranking order, and the tool works without an API key under a free tier with per-IP daily limits. It does not mention pagination or rate-limit response behavior, keeping it out of 5 territory.

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, front-loaded with the core action and store scope, then ordering behavior, then auth/quota caveat. No filler or repetition.

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?

Complete enough for a read-only search tool: the purpose, result ordering, and auth/quota constraints are covered, and the schema fully documents parameters. The absence of any mention of result limits relative to `num` or rate-limit error behavior is a minor gap, but no output schema exists that would otherwise cover it.

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 all four parameters (num, query, store, country) are already documented with defaults, ranges, and enum meaning. The description adds no parameter-level syntax or format detail, so the baseline of 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?

States a specific verb (search) and resource (apps) with the scoping detail that it queries the App Store or Google Play by keyword. This distinguishes it clearly from siblings like sonar_app_lookup (fetch by id) and sonar_list_apps (list tracked apps).

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 implies usage (keyword search across two stores) but never names alternatives or says when to prefer this over sonar_app_lookup or sonar_list_apps. An agent must infer the routing from names alone.

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