cache_stats

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

States 'Read-only — no side effects' explicitly. No annotations are provided, so the description correctly handles behavioral disclosure. Could mention if any resource constraints exist, but overall sufficient.

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 sentences, no wasted words. Purpose is front-loaded, alternatives are clearly stated. Very efficient.

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 simple input (one ID) and no output schema, the description lists the types of stats returned (memory, hit/miss, etc.), which is sufficient for an agent to understand what to expect. No missing critical information.

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?

Only one parameter (instance_id) with schema description 'UUID of the cache instance (from list_instances)'. The tool description repeats 'instance_id identifies the target instance (obtain from list_instances)', adding no new meaning. Schema coverage is 100%, so baseline 3 applies.

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 starts with 'Get real-time stats for a cache instance' and lists specific metrics (memory usage, hit/miss rate, etc.). It clearly distinguishes from siblings like cache_get, cache_exists, and cache_ttl, which are for reading cached values or key-level info.

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?

Explicitly states that the tool is for monitoring, capacity planning, or debugging, not for reading cached values (use cache_get) or key-level info (use cache_exists/cache_ttl). Also tells how to get the instance_id (from list_instances).

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