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

Annotations already declare readOnly, idempotent, non-destructive and closed-world, so safety needs no restating. The description adds genuine value beyond them by telling the agent that returned entries carry an aclId consumed by access.update and access.revoke — a cross-tool chaining fact nothing else in the structured data conveys. It does not mention result volume or whether the space/sheet selector is exclusive.

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 short sentences, no filler, and the resource is stated before the downstream-consumer hint. Every clause earns its place.

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 an output schema present and annotations covering safety, the description needn't explain return values or permissions, and it is complete on the aclId → access.update/revoke linkage. The one real gap is the missing constraint that a spaceId or sheetId must be supplied, since both are technically optional in the schema.

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% and both parameters carry inline descriptions ('Or one sheet', 'The space (from workspace.structure)'), so the schema does the heavy lifting. The description's 'a space or a sheet' loosely adds the either/or framing and the spaceId provenance hint, but does not clarify that one selector is required given required=0. Baseline 3 applies.

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 names the resource precisely — the set of users and roles for a space or a sheet — which is specific enough to act on. It also implicitly distinguishes itself from the mutation siblings by framing itself as the reader that supplies aclIds. The verb 'read' is implied rather than stated, but the resource and scope are unambiguous.

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 phrase 'a space or a sheet' implies the two query modes and the sentence about aclId implies the follow-up workflow into access.update and access.revoke. However, there is no explicit when-to-use statement, no note that exactly one of spaceId/sheetId must be supplied (required is 0), and no comparison against member.read, which an agent could easily confuse with this.

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