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

Annotations already indicate a destructive write operation, but the description adds crucial behavioral detail beyond that: sending tokens replaces the design wholesale rather than merging changes. It also discloses the plan requirement. This gives the agent a strong understanding of the operation's side effects without contradicting the 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 two tight sentences. The primary purpose is front-loaded, followed by the most critical behavioral warning and the requirement. Every sentence earns its place with zero 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?

Given the complex nested schema and existing output schema, the description covers the key non-obvious points: full-object replacement semantics and plan requirement. The schema documents the parameters, and the annotations cover the safety profile, so nothing necessary for correct invocation 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?

Schema description coverage is 100%, so the baseline is 3. The description's 'send the full object' warning essentially repeats what the tokens property description already says, adding no new parameter-specific meaning. It neither hurts nor significantly helps beyond the schema.

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 opens with a precise verb-resource pair: 'Updates a certificate template.' It clearly differentiates from siblings like create_certificate, delete_certificate, get_certificate, and list_certificates by stating exactly which operation it performs and on what resource.

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 establishes clear context: this is for modifying an existing certificate template, and it warns that tokens must be sent as a full object. It mentions the Scale plan requirement, adding usage constraints. However, it does not explicitly name alternatives or state when not to use it, so it falls just short of full exclusion guidance.

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