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

Beyond the annotations, it discloses the real side effects and invariants: omitted principals lose access, empty grants[] is invalid because an Admin grant must remain, and ORGANIZATION/CLERK_ADMIN role restrictions. It also explains the default state for newly created objects (creator-only Admin, no CLERK_ADMIN) and warns about PRIVATE/PUBLIC/teamId misuse. This is materially more than annotation hints.

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 front-loads the core action and scope, then layers constraints, workflow, and examples in a logical order. It is long, but every sentence carries a distinct rule or procedure, and the two examples make the complex grant array concrete.

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 write tool with no output schema, the description covers everything required to invoke it correctly: complete grant semantics, required invariants, prerequisite calls, principal resolution, and example payloads. The only omitted item is the return value, which is not needed for a set-permissions operation.

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?

Although the schema already covers the parameters (100%), the description adds meaning the schema does not: 'full replacement', 'omitted principals lose access', role rules per principal type, and exact examples with principalType/userId/teamId/role combinations. It also explains how to resolve principals with list_users/list_teams. This transforms the grant array from a generic array into a guided operation.

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 first sentence names a specific action ('Replace the full grant list') and a bounded resource set ('dashboard, report, budget, or cost alert'), so the agent immediately knows what the tool does and that it spans four object kinds. It also references get_object_permissions, making the read/write pairing clear without requiring the schema.

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 gives a clear workflow: call get_object_permissions first, then send the full grants list, and resolve principals via list_users/list_teams. It does not, however, contain an explicit 'when not to use' or a direct alternative-tool selection, apart from the prerequisite read tool, so it falls just short of a 5.

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