Compare brands

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

Annotations already cover the safety profile (readOnly, idempotent, openWorld, non-destructive), yet the description adds genuine behavior beyond them: sequential execution, input-order preservation, early termination on first failure with partial results retained, and no retries. That partial-result semantics is exactly what an agent needs before deciding to call this in a pipeline.

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 tight sentences, front-loaded with the cardinality and profile scope, then the return shape, then the failure/negative constraints. No filler, though the telegraphic phrasing ('one exact profile', 'complete-market claim') costs a little clarity.

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 steps in and names the returned data (colors/fonts/logo counts) and the partial-result behavior on failure. A 5-param, enum-bearing tool would ideally mention the identifier_type routing trade-off, but the schema's own descriptions cover that adequately.

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 the baseline is 3, but the description adds order-preservation semantics ('preserving input order') and the 'one exact profile' constraint that the schema's account field only partially conveys. The distinctness of identifiers is restated rather than expanded, keeping it short of a 5.

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 action (read two to five unique identifiers), the resource (brand identifiers), and the output surface (colors/fonts/logo counts), which is clearly more than the tautological title 'Compare brands'. The 2-5 cardinality implicitly separates it from the single-brand siblings like get_brand, though it never names them explicitly.

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 closing sentence gives real when-not guidance ('no cross-account mixing or complete-market claim'), and 'stop at the first failure' tells the agent this is a bounded batch read. However, it never routes the agent to a named alternative such as get_brand for a single lookup or search_brands for market-wide work, so the selection guidance stays implied.

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