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

Annotations already provide readOnlyHint, idempotentHint, and destructiveHint, covering safety and side-effect expectations. The description adds no behavioral context beyond what the schema already states—no mention of return format, ordering, pagination, or key limits. It does not contradict annotations but adds zero transparency value.

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?

A single compact sentence that front-loads the verb and resource, with no filler or repetition. Every word earns its place, making it highly 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?

For a simple one-parameter tool with full schema coverage and strong annotations, the description is sufficient for an agent to understand what the tool does. It does not describe the output format, but listing keys generally implies an array of key names, so this is largely inferable. A brief example of the return structure would push it to a 5.

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 coverage is 100%: the prefix parameter is described as 'Filter keys by prefix'. The description echoes this and clarifies that filtering is optional, but it does not add additional meaning beyond the schema. Baseline 3 is appropriate here since the schema handles parameter documentation fully.

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?

Clearly states the verb 'List', the resource 'keys in the key-value store', and the optional prefix filter. This distinguishes it from siblings like scalix_kv_get (retrieve a single key) and scalix_kv_set (write a key) by focusing on enumeration.

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 gives clear context: use this tool to enumerate keys, optionally scoped by a prefix. It does not explicitly mention alternatives or when not to use it, but the purpose is unambiguous enough for a list operation. A pointer to kv_get for specific lookups would make it a 5.

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