Horizon Describe Row Access Policy

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

Annotations already declare readOnlyHint=true, idempotentHint=true and destructiveHint=false, so the safety profile is covered. The description adds only the shape of the returned metadata, which the output schema already supplies; it says nothing about required privileges or what happens if the policy is absent.

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 no filler; the returned fields are listed efficiently. It is terse to the point of underspecification on usage, but nothing is wasted.

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?

With full schema descriptions, an output schema, and read-only annotations, the essentials are covered. Missing is any note on privileges, failure behavior, or how to resolve the required policy_name via the list sibling, which matters for an openWorld read tool.

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% and each of the three parameters carries the quoting guidance, so the description correctly defers to the schema. It adds no extra meaning about how database/schema_name qualify policy_name, but the baseline 3 applies when the schema does the heavy lifting.

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 (Describe) plus the resource (a row access policy) and enumerates the fields returned (signature, filter expression, comment). The describe-vs-list distinction against horizon_list_row_access_policies is inferable from the naming, but the description never says it explicitly.

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?

No when-to-use statement, no prerequisites, and no mention of the sibling horizon_list_row_access_policies as the way to discover policy names first. The agent must infer usage entirely from the tool name.

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