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

Annotations already flag destructiveHint=true and idempotentHint=true; the description adds value beyond that by disclosing persistence across sessions and the optimistic-concurrency behavior (etag returned, if_match guards against clobbering). It stops short of describing what happens to a hidden/unmentioned content_type on overwrite or the exact write-vs-update failure modes, so not a 5.

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?

Three short sentences, front-loaded with purpose, then the value/value_base64 rule, then the concurrency hint. Nothing is padded and each sentence carries distinct information.

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 an 8-parameter mutation with no output schema, the description covers the return payload (the etag) and the important write semantics. Secondary parameters like content_type and passport_token are left entirely to the schema, which is acceptable given full schema coverage but leaves room for slightly richer context.

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%, so the baseline is 3, but the description adds a cross-parameter constraint the schema does not encode: exactly one of value or value_base64. It also frames the etag workflow for if_match rather than just restating its definition.

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 specific verb and resource (store a value in your memory locker under a key) plus the defining trait that it persists between sessions. It also names locker_get as the etag source, which implicitly separates it from the read/delete/list siblings in the locker_* family.

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?

Explicitly tells the caller to send exactly one of value or value_base64, and explains the concurrency contract (pass etag as if_match so an overlapping run cannot silently overwrite). It gives clear usage context but never names an alternative tool or states when not to use this instead of, say, share_set or queue_put.

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