Describe Redis cache table

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

Annotations already declare readOnlyHint=true, confirming safe read operation. The description adds value by detailing error conditions (table doesn't exist or isn't redis_fdw) and the complete return structure. It could mention permissions or latency but is sufficient given the annotation context.

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?

The description is concise, front-loaded with the core action, and every sentence adds value: purpose, attributes, error behavior, return structure, and an example. No wasted words.

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?

Given the presence of an output schema, the description still provides valuable return structure details, enhancing completeness. It covers purpose, parameters implicitly, errors, and output, but lacks explicit parameter descriptions or prerequisites. Still, it is fairly complete for a simple descriptive 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 description coverage is only 33% (only the database parameter is described in the schema). The description does not explain the 'schema' and 'table' parameters, relying solely on their names. With low coverage, the description fails to compensate for the missing parameter details, resulting in a score of 2.

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 clearly states the tool describes a foreign table backed by redis_fdw, listing specific attributes such as server mapping, key structure, key-prefix, TTL, and column shape. It distinguishes itself from siblings like describe_table by specifying the redis_fdw requirement and from other describe tools by targeting Redis cache tables.

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?

The description implicitly indicates when to use the tool—for Redis-backed foreign tables—but does not explicitly state when not to use it or provide alternatives. However, the specificity of 'redis_fdw' makes the intended use case clear, earning a 4.

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