kv_keys_count

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

No annotations are provided, so the description must disclose behavioral traits, but it only states the action. It does not mention whether the operation is read-only, what the return format is (e.g., a number vs. an object), or any performance implications. This is a significant gap for an agent invoking the 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 a single, focused sentence that front-loads the core action ('Count total keys') followed by the optional modifier. There is no wasted verbiage.

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 tool is simple and the schema covers all parameters, but the description omits the return value format (expected for a count operation) and any edge-case behavior (e.g., empty namespace). Without an output schema or annotation, this leaves some ambiguity.

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 100%, so the parameters are already fully documented. The description adds no extra meaning beyond restating the optional prefix filter, which is already in the schema. Baseline 3 is appropriate.

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's function: 'Count total keys in a KV namespace' with an optional prefix filter. The verb 'Count' and resource 'KV namespace' distinguish it from sibling tools like kv_keys_list (which lists keys) and kv_key_get (which retrieves a single key).

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 implies usage when a count of keys is needed, but it does not explicitly mention alternatives or provide exclusions. There is no guidance on when to choose this over kv_keys_list or other tools, leaving the agent to infer from the tool name and purpose.

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