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

Annotations already declare readOnlyHint=false and destructiveHint=false, so the safety profile is covered. The description adds only the null-clearing behavior, which the schema also states, and says nothing about permissions required, whether the change propagates to synced events, or reversibility.

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, front-loaded with the action and immediately followed by the one non-obvious behavior. The second sentence largely duplicates the schema's nickname description, which is the only slight waste.

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 simple two-parameter mutation with full schema coverage and annotations covering safety, the description is sufficient to invoke correctly. Missing details (prerequisites, side effects on sync) are minor for this tool's complexity.

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 100%: both account_id (UUID) and nickname (max 50 chars, null to clear) are fully documented in the schema. The description merely restates the null-to-clear semantics without adding format, constraint, or edge-case detail beyond it.

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 verb and resource: set or clear the nickname for a connected calendar account. It is unambiguous and distinct from the other account-level siblings (list_accounts, reauth_account, disconnect_account), though it does not explicitly name a contrast case.

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?

Usage is implied by the purpose (rename an account after connecting it), but there is no explicit when-to-use/when-not guidance, no note that the account must already be connected, and no mention of alternatives for editing other account attributes.

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