redis_exists

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

With no annotations, the description carries full responsibility for behavioral disclosure. It states the main operation (counting existing keys) but omits details such as return type (integer count vs boolean), behavior on empty arrays, error handling, or whether the operation is read-only. Minimal transparency beyond the basic action.

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?

Single sentence with no filler. The description efficiently communicates the core functionality, front-loading the verb and subject. No unnecessary detail or repetition.

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 simple tool with one parameter and no output schema, the description covers the essential behavior. 'Count' implies a numeric return, and 'currently exist' clarifies that non-existent keys are ignored. Lacks explicit notes on permissions or edge cases, but given the low complexity, the description is largely sufficient. Not perfect because it doesn't mention potential pitfalls like empty arrays or large key lists.

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 0%, so the description must compensate. The phrase 'given keys' explicitly links the 'keys' parameter to the counting action, adding semantic meaning beyond the schema's type definition. However, it does not elaborate on format, limits, or edge cases, leaving some ambiguity. Adequate but not strong.

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 ('count') and resource ('given keys'), clearly indicating it checks existence. Does not explicitly name alternative sibling tools, but the action is distinct enough from redis_mget or redis_get that an agent can likely infer the purpose. Missing explicit contrast with siblings prevents a 5.

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 guidance on when to use this tool versus alternatives. The description gives no context about when existence counting is preferable to retrieving values (redis_mget) or other key operations. An agent receives no direction on selecting this tool.

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