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

Annotations already declare read-only, idempotent, and non-destructive behavior. The description adds valuable scoping context (anonymous IP, BYO key hash, or account ID) and explains the dual behavior of retrieving a value or listing all keys when omitted. It does not mention return format or missing-key handling, but this is acceptable given the annotations.

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 carrying necessary information: the core action, the lookup purpose, and scoping plus sibling tools. No fluff or repetition; key details are front-loaded.

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 tool with one optional parameter and no output schema, the description covers all essential aspects: what it does, when to use it, how scoping works, and how it relates to remember and forget. The annotations handle the safety profile, so no further disclosure is needed.

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 description for the only parameter 'key' is fully descriptive: 'Memory key to retrieve (omit to list all keys).' The tool description reinforces this behavior but introduces no additional semantic details such as format constraints or defaults. Since schema coverage is 100%, the 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 uses specific verbs ('retrieve', 'list') and identifies the resource (values saved via remember). It clearly distinguishes itself from sibling tools by explaining the counterpart tools for saving (remember) and deleting (forget), and immediately clarifies the listing capability.

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?

It explicitly states when to use the tool: 'Use to look up context the agent stored earlier' and provides direct alternatives: 'Pair with remember to save, forget to delete.' This gives clear guidance on appropriate use cases and related tools.

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