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

No annotations are provided, so the description must carry the behavioral burden. It does disclose the key expiry and not-found behavior, which is useful. However, it omits other behavioral traits such as whether it overwrites existing keys, atomicity, or error handling. For a mutation tool without annotations, this is partial transparency.

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 no extraneous words. The key behavior (TTL expiration) is front-loaded, and the secondary sentence clarifies the semantic outcome. Efficient and well-structured.

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?

Given no annotations, no output schema, and 5 parameters with low schema coverage, the description is incomplete. It does not cover authentication (owner_key), the role of slug, or the exact semantics of ttl_seconds beyond the name. An agent would need additional context to call this tool 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 20% (only owner_key is described). The description adds no parameter-level detail: it does not explain slug, key, value, or ttl_seconds beyond their names. It says 'JSON value' but does not clarify the format or constraints. With such low schema coverage, the description fails to compensate for the missing parameter documentation.

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?

States a clear verb ('Store') and resource (JSON value under a key) with a specific TTL property. It explicitly mentions the TTL behavior, distinguishing it from sibling tools like kv_put (which likely lacks TTL) and kv_get (retrieval). The purpose is unambiguous.

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 TTL is needed but does not explicitly say 'use this instead of kv_put when you need expiration' or mention any alternatives. It provides context but lacks explicit routing guidance compared to the top example.

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