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

Adds real behavioral context beyond the annotations: this is a WHOLESALE replace, an omitted description CLEARS the field, and display_name is required. That is exactly the kind of data-loss nuance destructiveHint=true only hints at. Slightly short of 5 because it doesn't address validation failures or what the response confirms.

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?

Front-loaded with the scope statement, then the non-goal, then the replacement hazard, then the safe procedure. Three sentences, no filler, and the most dangerous fact (description is cleared if omitted) is stated before the remedy.

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 3-parameter mutation with an output schema available, the description covers scope, exclusions, destructive replacement semantics, required fields, and the read-before-write procedure. Nothing an agent needs to avoid data loss 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 coverage is 100%, so baseline is 3; the description earns above that by explaining the wholesale-set semantics of description and the immutability of slug, which the schema does not state. It does not add format or length constraints for display_name beyond 'cannot be blank' already in 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?

States a specific verb (update) and resource (api template) plus the exact field scope: display_name and description, metadata only. It explicitly distinguishes itself from create_api_template_version, which authors the request definition, so an agent can route without inspecting schemas.

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?

Gives explicit when-not guidance (this does NOT change the request definition — use create_api_template_version) and names an immutability constraint (slug cannot be changed). It also prescribes the correct call pattern: read current values with get_api_template first and pass both fields.

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