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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false. The description adds meaningful behavioral context beyond annotations: it explains the 'list all keys' behavior when the key argument is omitted, the scoping to an identifier, and the complementary relationship with remember and forget. This goes beyond the minimal annotation coverage without contradicting it.

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 two sentences long, front-loads the primary action, and packs useful details (examples, scoping, sibling pairing) without padding or repetition. Every sentence earns its place.

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?

This is a low-complexity tool (one optional parameter, no output schema). The description covers what it returns (a value or list of keys), when to use it, how it's scoped, and how it relates to sibling tools. Nothing essential is missing for an agent to select and invoke it 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%, so the baseline is 3. The description adds value by providing concrete examples of what keys might contain ('user's target ticker, an address, prior research notes'), which helps the agent form a mental model of valid inputs. It also clarifies the omit-key behavior for listing, which the schema already states but the description reinforces with context.

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 starts with a specific verb 'Retrieve' and clearly states the resource (values previously saved via remember) and the dual behavior of listing all keys when the argument is omitted. It inherently distinguishes itself from sibling tools 'remember' and 'forget' by describing its read-only retrieval role.

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 explicitly says 'Use to look up context the agent stored earlier' and then pairs the tool with 'remember to save, forget to delete.' This provides clear when-to-use guidance and implicitly states when not to use (for saving or deleting). The scoping note (anonymous IP, BYO key hash, account ID) adds important context.

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