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

Annotations already declare destructiveHint=true and readOnlyHint=false, covering the mutating nature. The description adds the behavioral nuance that a custom template gets saved inline as a new named template, which is useful context. It does not disclose any additional side effects like potential overwrites or permission requirements, but given annotation coverage, it is adequate.

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, dense sentence that front-loads the core action ('Create a new automation') and then explains the two modes. It is concise and free of fluff, though the second clause is slightly complex. It earns points for efficiency and clarity.

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?

Given the tool's complexity (13 params, 10 required, nested object, output schema exists), the description covers the key decision point (existing vs custom template) and references the source tools for IDs. It omits mention of required fields like parent_id or the meaning of date_text, but these are fully covered in the schema. The output schema handles return values. It is sufficient but not exhaustive for such a complex tool.

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 each parameter is already documented. The description reinforces the relationship between template_id and the custom payload, but this is also stated in the schema (template_id description and custom description). It adds no new parameter meaning beyond what the schema provides, so a baseline of 3 is appropriate.

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 clearly states 'Create a new automation', identifying the specific verb and resource. It distinguishes this tool from siblings by explaining the two creation modes: using an existing template/sender or providing a custom template inline. This differentiates it from create_email_template and create_email_sender while clarifying its own scope.

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 description gives explicit guidance on the two valid usage paths: referencing existing templates/senders by id from the listed tools, or using the 'custom' literal with a payload. This helps the agent decide which parameters to fill. However, it does not explicitly contrast with update_automation or test_automation, nor state when not to use it, though the 'create' intent is clear.

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