cachly-mcp-server

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

With no annotations provided, the description carries the full burden and does well by disclosing important behavioral traits: it uses SCAN to avoid blocking the server (performance characteristic), returns at most `count` keys (limitation), and mentions glob pattern syntax examples. It doesn't cover error conditions, permissions, or rate limits, but provides solid operational 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?

Two sentences with zero waste. The first sentence establishes purpose and key parameters, the second adds behavioral constraints. Every word earns its place, and the most important information (what it does) comes first.

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 read-only listing tool with 3 parameters and no output schema, the description provides good coverage: purpose, parameters, behavioral constraints, and implementation detail (SCAN). It could mention return format or pagination behavior, but given the tool's relative simplicity and lack of annotations, it's mostly 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?

With 67% schema description coverage (2 of 3 parameters have descriptions), the description adds meaningful context beyond the schema. It explains what the pattern parameter accepts ('glob pattern (e.g. "user:*", "session:*")') with concrete examples, and clarifies that count is a maximum limit ('Returns at most `count` keys'). This compensates well for the partial schema 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?

The description clearly states the specific action ('List keys'), resource ('in a cache instance'), and scope ('matching an optional glob pattern'). It distinguishes from siblings like cache_get (retrieve values), cache_delete (remove keys), and cache_stats (get statistics) by focusing on key enumeration with pattern filtering.

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 clear context for when to use this tool: when you need to list cache keys with optional pattern matching. However, it doesn't explicitly state when NOT to use it or name specific alternatives among the many cache-related siblings, though the pattern-matching feature implicitly differentiates it from simpler listing tools.

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