update_mailing_list

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

Annotations already declare readOnlyHint=false, idempotentHint=true and destructiveHint=true. The description adds two genuinely new facts beyond that — partial-update semantics and that subscribers are preserved — which is real value. However, it does not address the tension with destructiveHint=true (what actually gets overwritten, or whether a type change from public to private affects subscribers), leaving the destructive flag unexplained.

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 with no filler: the first defines scope, the second and third each carry a distinct behavioral guarantee. The most decision-relevant facts are front-loaded.

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 6-parameter mutation tool with full schema coverage, no nested objects and no output schema, the description covers mutation scope, partial-update behavior and subscriber safety. Minor gaps remain: what the response looks like and whether changing type/opt-in affects existing subscribers' status.

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%, so baseline is 3. The description goes slightly beyond by naming the mutable fields in prose and, more importantly, stating that omitted fields are not sent — semantic partial-update behavior the schema alone (which only marks list_id required) does not spell out.

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 (Update) and resource (mailing list) and enumerates the mutable fields (name, type, opt-in mode, tags, description). Sibling differentiation is implicit — the 'existing subscribers are not removed' clause separates it from delete_mailing_list, but no sibling is named explicitly.

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 sentence 'Only the fields you provide are sent' tells the agent how to call it (partial update), which is useful implied guidance, but there is no statement of when to prefer this over update_subscriber or create_mailing_list, and no prerequisites or exclusions.

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