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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint false. The description adds valuable context: the tool is scoped to an identifier (anonymous IP, BYO key hash, or account ID), which explains data isolation, and that omitting the key lists all saved keys. This goes beyond the annotations without contradicting them.

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?

The description is three sentences, front-loaded with the primary action, and every sentence adds value: what it does, when to use it, and how it relates to siblings. No redundancy or filler.

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 the simple one-parameter schema, strong annotations, and no output schema, the description is fully complete. It covers the main use case, scope, and pairing with sibling tools, making it easy for an agent to select and invoke 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 coverage is 100% with the key parameter fully described. The description adds additional meaning by explaining that omitting the key triggers list-all behavior, and clarifies the semantic relationship to remember and forget. This exceeds the bare schema description.

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 retrieves a previously saved value via remember or lists all saved keys when the key argument is omitted. It names the resource (saved memory) and the verb (retrieve/list), and distinguishes itself from 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?

It explicitly explains when to use: 'to look up context the agent stored earlier... without re-deriving it from scratch.' It also pairs with remember and forget, providing clear context on how it fits into the workflow, and implicitly when not to use (when you want to save or delete, use those alternatives).

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