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

No annotations are supplied, so the description carries the full burden of behavioral disclosure and largely drops it. It does not say whether existing content is overwritten or lost, whether the update is partial or full-replacement, whether permissions are required, or whether prior versions are recoverable. The only behavioral hint is 'and/or', which suggests field-level optionality but conflicts with the schema making content required.

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?

A single front-loaded sentence with the verb, resource, and mutable fields in order. There is no redundant filler and nothing is buried.

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?

This is a mutation tool with no annotations and no output schema, so the description is the only place to learn about overwrite semantics and required permissions, and it covers neither. An agent could call it correctly by shape but not confidently predict the side effects of replacing HTML content.

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 100% with per-parameter descriptions ('New name.', 'The template slug to update.', 'New HTML content.'), so the baseline of 3 applies. The description's 'name and/or HTML content' phrasing adds a small optionality nuance but actually blurs the fact that content is a required parameter, so it does not add reliable meaning 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 gives a specific verb and resource ('Update ... an existing template') and names the mutable fields (name, HTML content), which distinguishes it from create_template and delete_template in the sibling list. It stops short of explicitly naming those siblings as alternatives, so it is clear but not fully differentiated.

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?

Usage is only implied: the word 'existing' plus the verb 'update' signals this is for modifying a template that already exists rather than creating one. There is no explicit statement of when to choose this over create_template or generate_from_template, and no prerequisites or caveats are given.

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