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

Annotations are empty, so the description carries the burden. It discloses the read-only nature ("List"), the permission scope (only accounts the connected account "can read"), the returned fields, and how the id feeds downstream tools. It does not mention pagination, rate limits, or error behavior, but for a simple account lister this is solid context.

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 sentences, front-loaded with the tool's purpose and output fields, followed by the actionable downstream hint. Every clause 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?

There is no output schema, but the description enumerates the fields the tool returns and explains how the result connects to other merchant_* tools. For a simple account-discovery tool with one optional parameter, nothing essential is missing.

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 single optional email parameter is already documented in the schema. The description mentions "the id as `account`," but that refers to passing the returned account id to other merchant_* tools, not to this tool's email parameter, so it adds little semantic meaning beyond the schema. Baseline 3 is appropriate.

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 gives a specific verb ("List"), resource ("Google Merchant Center accounts"), scope ("the connected Google account can read"), and enumerates the exact fields returned (id, name, homepage, language, time zone). It also names the downstream merchant_* tools that consume the returned id, distinguishing it from the other account-listing siblings.

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 clearly states the use case: discover accounts and pass the resulting id as `account` to other merchant_* tools. There is no explicit when-not guidance or named alternative sibling (e.g., ads_accounts), so it stops short of a full 5, but the context is unambiguous.

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