Compare stores

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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive, openWorld), so the bar is lower, yet the description adds genuinely non-obvious behavior: null values when the app is absent from a store, the diff direction (bazaar minus myket), and the caveat that ratings are not shared between stores. It does not mention auth, rate limits, or error behavior, so it falls short of a full behavioral picture.

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?

Front-loads the compared fields, then the return shape and diff semantics, in two tight sentences. Every clause carries information; nothing is redundant with the name or title.

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?

With no output schema, the description must explain the return value, and it does: per-store figures plus a diff identifying the newer version and the rating delta. Combined with full annotation coverage, an agent has everything needed to call and interpret this tool.

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?

There is a single parameter with 100% schema description coverage, including format and examples ('ir.mci.ecareapp'), so the schema carries the semantics. The description only refers to it obliquely as "one package" and adds no syntax or constraint detail beyond the schema.

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 (compare) and resource (one package across Cafe Bazaar and Myket) and enumerates exactly which fields are compared: version, rating, rating count, installs, size, update date, price. This is clearly distinguishable from siblings like ap_app (single-store detail) or ap_search.

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 concrete use-case triggers ("is the app up to date on Myket?", "which store rates it higher"), which tells the agent when this tool is the right pick. It stops short of explicitly naming when NOT to use it or pointing to ap_app/ap_search as the single-store alternative, so it is clear context rather than full routing guidance.

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