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

Adds significant behavioral context beyond annotations: it discloses that the operation changes stored data (consistent with destructiveHint=true), fires the template.updated webhook, cannot move the template to another project, and does not generate an image. These details are not present in the annotations and give the agent a precise understanding of side effects and limitations.

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?

Three sentences, each carrying distinct information: the action and scope, side effects and constraints, and a user-confirmation directive. No filler, and the most critical information (what it does and how it resolves the target) is front-loaded.

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 tool with an output schema and annotations, the description covers all necessary operational details: target resolution, side effects, immutability constraint, non-image-generation, and confirmation requirement. The output schema handles return value documentation, 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?

Schema description coverage is 100%, so parameters are already well-documented. The description adds value by clarifying the resolution semantics for templateIdOrName (exact id or name) and the partial-update concept ('selected fields'), which the schema does not explicitly state. This elevates it above the baseline 3.

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 (overwrite), resource (Imagelato resizing and reformatting preset), and resolution method (exact id or name). Clearly distinguishes from siblings like add_template (creates new) and get_template (reads). The description also notes what it does not do (generate an image) and a key constraint (cannot move project), making its purpose unambiguous.

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?

Provides clear context for when to use (updating an existing template) and includes an explicit user-confirmation requirement. It does not explicitly name alternatives like add_template, but the 'does not generate an image' and 'cannot move to another project' statements help delimit its scope. A dedicated when-not-to-use note would push this to 5.

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