cache_stats

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

The description explicitly states the tool is read-only with no side effects, which is essential behavioral information. However, with no annotations provided, the description could also mention potential error handling (e.g., what happens if instance_id is invalid) or rate limits, though the given context is still satisfactory for a monitoring tool.

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 with four sentences, each adding value: first sentence states purpose and metrics, second asserts safety, third explains parameter, fourth gives usage guidance and links to siblings. 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?

The description covers purpose, parameter, usage context, and differentiators. It lists the metrics returned, which helps set expectations without an output schema. It does not explain error handling, but for a simple read-only tool, it is largely complete.

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?

The input schema has 100% description coverage, so the schema already describes the instance_id parameter. The description adds guidance to obtain the ID from list_instances, which reinforces but does not significantly expand beyond the schema.

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 retrieves real-time stats for a cache instance and enumerates specific metrics like memory usage, hit/miss rate, commands/sec, connected clients, keyspace info, and uptime. It also distinguishes itself from sibling tools by explicitly stating it is not for reading cached values (use cache_get) or key-level info (use cache_exists or cache_ttl).

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 provides explicit guidance: use for monitoring, capacity planning, or debugging performance issues; do not use for reading cached values or key-level information, with specific sibling tool references. This gives clear when-to-use and when-not-to-use instructions.

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