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

With no annotations provided, the description carries the full burden for behavioral disclosure. It adds the max 1 MB constraint but omits critical behaviors such as whether an existing key is overwritten, whether authentication is required, or what happens on failure. 'Store' implies mutation, but no safety or side-effect information is given.

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, efficient sentence that is front-loaded with the core action and resource. Every word adds value, and there is no redundancy or filler.

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 write operation with no annotations, no output schema, and sparse parameter descriptions, the description is inadequate. It does not mention when to use it, overwrite behavior, return values, or any side effects beyond max size. The tool appears to be a fundamental KV store operation but lacks the behavioral context needed for an agent to invoke it correctly.

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 only 33% (only 'id' is described as 'vault id'). The description adds the max size for 'value' but does not clarify the meaning of 'key' or the relationship between id and key, nor does it specify expected formats. The description compensates only partially for the sparse 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 states a clear action ('Store a value') and a clear resource ('in a vault'), with a specific size constraint. It distinguishes from read operations like kv_get/kv_list but does not explicitly differentiate from sibling store_secret, which could be confused for a similar write operation.

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?

No guidance is provided on when to use kv_set versus alternatives like store_secret or create_vault. The description only states what it does, not the context or prerequisites for using it.

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