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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint=false, so safety is covered. The description adds real behavioral value beyond that: it returns a reason when export is blocked and discloses the underlying rule ('they need to cover its market'), which an agent cannot get from the schema. It omits any statement of return shape or whether the check is per-user vs per-workspace.

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?

One sentence, front-loaded with the core question and using the parenthetical efficiently to explain the blocking reason. The parenthetical is slightly awkwardly attached, but no sentence is wasted.

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 single-parameter read-only eligibility check this is nearly sufficient: it conveys the question answered, the yes/no-plus-reason nature of the result, and the gating rule. An agent could still want confirmation that it should be called before export_model, but no structural gaps remain.

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?

The single 'id' parameter is fully documented in the schema, including the accepted ch:… id or datasnack.ai/m/… URL forms. The description adds no parameter meaning at all, but with 100% schema coverage the schema carries this dimension adequately.

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 states a specific check ('whether the signed-in reader can export a model to Excel now') tied to a named resource and format, which separates it from the action sibling export_model. It stops short of naming that sibling, so the distinction rests on inference from phrasing rather than explicit contrast.

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 phrasing 'can export ... now' implies a pre-flight eligibility check before attempting export_model, but the description never says so outright and lists no exclusions or prerequisites. Usage is inferable rather than stated.

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