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

Annotations already provide idempotentHint=true and destructiveHint=false. The description adds the meaningful constraint that element IDs must reference existing elements, but it does not clarify whether existing overrides are replaced or merged, what happens on invalid IDs, or how the optional 'state' parameter affects behavior. No contradiction with annotations.

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 description is a single front-loaded sentence with a concrete JSON example. The example earns its place because the elements schema leaves additionalProperties open, so showing real override keys is the clearest way to communicate the expected shape.

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 4-parameter mutation with no output schema, the description captures the input shape and the key cross-element constraint. However, it does not explain the semantics of the 'state' parameter, nor whether overrides are additive or replace existing locale content. Annotations cover safety, but behavior around state remains unclear.

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%, so the schema already documents all four properties. The description adds value by emphasizing that 'id' must reference an existing element and by demonstrating title/content fields in the example, matching the open additionalProperties of elements. It does not add detail for notification_id, locale_id, or state beyond their schema descriptions.

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 uses a specific verb 'Set' and names the exact resource: 'locale-specific content overrides for a V2 notification template.' This clearly differentiates the tool from sibling content tools like put_notification_content or put_notification_element, and the concrete Spanish example removes any ambiguity about intent.

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 phrase 'locale-specific content overrides' implies when to use this tool, and the instruction that each element must reference an existing ID is a useful prerequisite. However, it does not explicitly contrast with alternatives such as put_notification_content, put_notification_element, or update_translation, nor does it state when not to use this tool.

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