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

Annotations already establish read-only, idempotent, and non-destructive behavior. The description adds useful context beyond those: it can list all saved keys when key is omitted, and it is scoped to the caller's identifier, which has privacy implications. No contradictions with annotations exist, and the added detail is valuable.

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, with the primary action stated up front. Each sentence earns its place: one explains retrieval and listing, one gives use cases, and one describes scoping and complementary tools. No redundant or filler content.

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 single optional parameter with no output schema, the description covers the tool's purpose, usage context, scoping, and relation to sibling tools. It fully answers what the tool does, when to use it, and how it fits into the memory lifecycle, making it complete for the tool's simplicity.

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 schema already documents the key parameter and its omit-to-list-all behavior, so description coverage is 100%. The description reinforces this by tying the key to values saved via remember, but it does not add significant new meaning beyond what the schema provides. Baseline 3 is appropriate for high schema coverage.

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 opens with a specific verb and resource ('Retrieve a value previously saved via remember'), and also clearly distinguishes the list-all-keys behavior when the key argument is omitted. It is easily differentiated from sibling tools like remember and forget, which are explicitly named for the save/delete counterparts.

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 clearly states when to use this tool: to look up context the agent stored earlier, avoiding re-derivation. It also provides scoping context (anonymous IP, BYO key hash, or account ID) and points to complementary tools (remember to save, forget to delete). However, it does not explicitly name alternatives to avoid or state when not to use it, stopping short of a 5.

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