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

Annotations already declare readOnlyHint=true, idempotentHint=true, destructiveHint=false, openWorldHint=false, so the safety profile is fully covered. The description adds useful context: the JSON-style scoping paragraph indicates the return shape and that 'project' changes the view. No auth/permission requirements or rate limits are mentioned, so it's adequate but not rich.

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?

The single-property description is a run-on sentence with comma-dangled list items and a sentence fragment ('project: the given ...'). It mixes return-value enumeration, parameter semantics and scope notes without clear sentence boundaries, making it effortful to parse. Not front-loaded on the primary purpose.

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?

Annotations cover safety and the input schema fully documents app_id, so no safety or parameter details are missing. However, with no output schema and a verbose, loosely structured description, an agent must parse the paragraph to infer the return structure. It's usable but not complete or crisp for a tool enumerating many mailbox fields.

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% for the single parameter: the input schema already documents app_id fully (UUID format, 'Project id from list_apps. Omit to use your most recently added project.'). The description adds the concept that 'project' returns the given or newest project's mailbox and From, but doesn't give syntax beyond what the schema says. 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?

States a specific resource (Gmail mailboxes) and enumerates the exact data returned: read access status, free mailbox flag, plan limit status, warm-up, aliases, and sending projects. It's a clear list/retrieve verb with a detailed resource. However, it doesn't explicitly distinguish itself from close siblings like get_mailbox_connect_link or list_apps, so it doesn't reach 5.

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 a read/list use case and notes that connecting, disconnecting and revoking happen in the dashboard, which softly brackets its scope. But there is no explicit when-to-use, when-not-to-use, or routing to alternatives (e.g. get_mailbox_connect_link for authorization). The paragraph about 'project:' hints at an alternate view but doesn't state selection criteria.

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