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

The readOnlyHint annotation already establishes that this is a safe discovery operation. The description adds useful behavioral context: it returns workspace/brand/project metadata, available read-only actions, and action-specific request details. It does not cover failure modes or rate limits, but the annotations lower the burden.

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 description is front-loaded, clearly structured as Step 1, Step 2, and Optional calls, and every sentence contributes to correct invocation. The note that available_actions is already included in the accounts response is useful rather than redundant.

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?

For a setup/discovery helper with a readOnly annotation and an output schema, the description is largely complete: it explains the intended workflow and the information returned by each request mode. The main gap is that the platform parameter is never explained and the actions parameter's string-or-array flexibility is not mentioned.

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 0%, so the description must carry parameter meaning. It explains the request enum modes, the required actions list for actions_details, and the brand_id + workspace_id combination for brands. It does not explain the platform parameter or note that actions can be a single string as well as an array, so it is strong but not complete.

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 clearly frames the tool as a BigQuery planning/setup helper and enumerates the request modes it supports. It distinguishes itself from pure querying by positioning itself as the prerequisite discovery step, though it does not explicitly name or contrast with the sibling tools.

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 gives explicit step-by-step usage: first request='accounts', then request='actions_details' with actions and notes that this is REQUIRED before querying. It also identifies the optional modes and when to use them, leaving little to inference.

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