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

Annotations already cover the safety profile (readOnlyHint, idempotentHint, non-destructive, closed-world), so the description's job is to add context beyond that — and it does, disclosing that the response is a deep object including conditions, action, schedule, attached campaigns, and each pair's last run result. No output schema exists, so this payload sketch is genuinely informative. It omits failure behavior for an unknown id, which keeps it from a 5.

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?

One tight sentence fragment with zero filler, and the most important element — what comes back — is front-loaded. The only structural weakness is that it lacks a verb, reading as a bare noun phrase rather than a statement of what the tool does.

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 single-parameter read with full annotation coverage and no output schema, the description supplies the one thing structured data cannot: the shape of the returned object. What remains missing is error/empty behavior for a nonexistent id and any hint about relationship to the attach/detach rule tools.

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?

There is a single parameter with 100% schema description coverage ('Auto-rule id'), so the schema already carries full parameter meaning. The description adds nothing about the id's format, provenance, or where an agent obtains it (e.g., from list_auto_rules), leaving the baseline 3 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 names the specific resource ('One auto-rule') and enumerates the payload it carries — conditions, action, schedule, attached campaigns with last run results — which implicitly separates it from the plural sibling list_auto_rules. It stops short of an explicit verb or a direct contrast with preview_auto_rule or list_auto_rule_runs, so the distinction is inferable rather than stated.

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?

There is no when-to-use guidance at all: nothing says to call this when you already have an auto-rule id, nor when to prefer list_auto_rules for discovery or preview_auto_rule for dry-run evaluation. The usage is only weakly implied by the word 'One' and the required id parameter.

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