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

Annotations declare destructiveHint=true and idempotentHint=false, but the description adds the crucial detail of *what* is destroyed: conditions and actions are replaced whole, not merged. It also discloses a non-obvious data hazard (outgoing addresses are hidden on read-back, so a read-modify-write round trip silently drops them). That is exactly the beyond-annotation context a mutation tool needs.

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?

The action verb and the primary instruction are front-loaded in the first sentence, and every subsequent clause is load-bearing. The second sentence is long and clause-stacked, slightly reducing scannability, but there is no filler.

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 7-parameter destructive patch tool with no output schema, the description covers the two things most likely to cause a bad call: destructive replacement semantics and the masked-address rebuild rule. The heavy nested actions/conditions schemas already document parameter content, and annotations carry the safety profile, so nothing essential is missing.

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?

With only 29% top-level schema description coverage, the description carries extra burden, and it partially meets it by defining patch semantics for the two complex fields (conditions/actions replace wholesale). However, it adds nothing about automation_rule_id sourcing, event_name, active, or the field-level meaning of the remaining parameters, so it only partly compensates for the coverage gap.

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+resource ('Change an automation rule') so the agent knows exactly what object it mutates. It does not, however, distinguish itself from the very close siblings toggle_automation_rule, create_automation_rule, or get_details_of_a_single_automation_rule, leaving the agent to infer the boundaries from the name alone.

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 clear operative guidance for how to call it: send only the fields being changed, and never resend a read-back list. What is missing is when to prefer this over its alternatives — e.g. flip 'active' via toggle_automation_rule rather than an update — so usage context is clear but alternates are never named.

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