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

With no annotations provided, the description carries the full burden of behavioral disclosure. It does not state whether writing to an existing key overwrites the value, whether there are any size limits, or what happens when the slug is invalid. It also doesn't mention the owner_key parameter or its default behavior, which is crucial for org-scoped operations.

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 sentence with no wasted words, front-loading the core action. It is appropriately concise for a simple store operation, but it could have been slightly more informative about overwrite semantics without losing brevity.

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 mutation tool with no annotations and no output schema, the description is incomplete. It fails to clarify whether the key is overwritten, how owner_key affects behavior, or any error conditions (e.g., invalid slug). An agent might incorrectly assume it's safe to call without understanding side effects, making this insufficient for reliable invocation.

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?

The input schema already describes slug, value, and owner_key, covering 75% of parameters (only 'key' lacks a description). The description adds minimal extra meaning, just implying the value is JSON and the key is in a namespace, which is already implicit in the schema. Since schema coverage is high, a baseline of 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 states a clear verb ('store'), a specific resource ('a JSON value under a key'), and scopes it to 'your namespace'. This distinguishes it from other KV tools like kv_get, kv_delete, and kv_list. However, it doesn't explicitly mention overwriting behavior or the requirement of a namespace slug, leaving a slight ambiguity in scope.

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 this tool versus alternatives such as kv_put_ttl (for TTL), kv_cas (for conditional writes), or kv_incr (for numeric increments). The description does not mention any exclusions or prerequisites, so an agent cannot determine the appropriate tool based on the description alone.

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