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

Adds behavior beyond the annotations: partial PATCH semantics, and the critical warning that triggers/actions/conditionNodes REPLACE rather than append — exactly the destructive consequence flagged by destructiveHint. It also discloses the required API-key scope (`automations:write`), which annotations cannot express.

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?

Four short sentences, each carrying distinct information: purpose, optionality, the replace-not-append hazard, the disable idiom, and the auth scope. The most dangerous trait (REPLACE) is front-loaded near the top.

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 destructive, non-idempotent mutation with 9 params and no output schema, the essential behaviors are covered: partial update, collection replacement, disable-vs-delete, and required scope. It does not mention failure modes (e.g. invalid action/trigger types, account selection errors) or what a successful update returns, which would round it out.

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 78% and the schema already documents the replace semantics for the three collection params, so there is some duplication. The description still adds meaning the schema lacks, notably that only specified fields change and the `active: false` idiom for disabling.

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?

Opens with a specific verb+resource ("Update an existing automation") and immediately scopes it against the create/delete siblings through the phrase "existing automation" plus the partial-update rule. An agent can distinguish it from pm_create_automation and pm_delete_automation without opening any 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?

Gives concrete when-to guidance: it is for changing only specified fields, and `active: false` is the intended path for disabling instead of deleting. It does not explicitly name pm_create_automation / pm_delete_automation as the alternatives for those cases, so routing is implied rather than spelled out.

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