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

Annotations already declare readOnlyHint=true and idempotentHint=true, so the description doesn't need to restate safety. It adds useful behavioral context beyond annotations: the scoping to the user's identifier (anonymous IP, BYO key hash, or account ID) and the dual retrieve/list behavior. This goes beyond the annotation coverage.

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 sentences, each earning its place: the first states the core action, the second identifies use cases, and the third explains scoping and related tools. No fluff, front-loaded with the action. Ideal size for the tool's simplicity.

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, the description covers the two modes of operation, scoping, and relations to remember/forget. It doesn't describe behavior on missing keys, but given the annotations and schema clarity, this is a minor gap. The tool is easy to use with the information provided.

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 provides 100% coverage for the single parameter 'key', including the note 'omit to list all keys'. The description repeats this but adds no new semantic meaning beyond the schema. Per the rubric, baseline is 3 when schema coverage is high, and there's no extra parameter insight.

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 clearly states the tool does two things: retrieves a saved value by key, or lists all keys when the key is omitted. It names the specific verb and resource (retrieve/list memory) and explicitly distinguishes itself from the sibling tools remember and forget.

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?

Provides clear when-to-use guidance: 'Use to look up context the agent stored earlier... without re-deriving it from scratch.' It also explicitly pairs with remember and forget, giving direct alternative/complementary tool context, which satisfies the when/when-not requirement.

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