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

Annotations already declare readOnlyHint=true, and the description adds meaningful context beyond that: it discloses what is returned (binding name, roleRef, subjects) and its listing behavior. It stops short of covering pagination or auth requirements, but adds solid value over the annotation.

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 tight sentences with no filler: purpose first, then return shape, then usage/differentiation. Every sentence carries information the agent needs.

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 no output schema, the description correctly takes on the burden of describing the return shape (name, roleRef, subjects) and the tool's diagnostic purpose. Nothing essential for correct invocation is absent.

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 the schema already documents all three parameters including the optional namespace. The description reinforces the optional RoleBinding behavior tied to namespace but adds no syntax or format detail beyond the schema, matching the baseline for full coverage.

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 (Fetch/List) and resource (ClusterRoleBindings, optionally RoleBindings), and explicitly distinguishes itself from the sibling describe_resource by noting it can list all bindings without requiring names upfront. An agent can identify the tool's function without opening the schema.

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 clear context — 'Use this to diagnose permission-denied errors' — and names the alternative (describe_resource) with the condition that selects this tool (listing without knowing names). Strong, though it doesn't enumerate explicit when-not scenarios beyond that single contrast.

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