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

Annotations already cover the safe read-only, non-destructive, idempotent nature. The description adds meaningful behavioral context beyond annotations: the ability to list all keys by omitting the key argument, and the identifier-based scoping. It doesn't mention potential edge cases like missing keys, but the core behavior is well disclosed.

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, front-loaded with the primary action. Every sentence contributes: the first explains the core function, the second gives a use-case rationale, and the third covers scoping and companion 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 tool with one optional parameter, no output schema, and strong annotations, the description is complete. It covers retrieval, listing, scoping, use case, and complementary tools, giving the agent everything needed to correctly invoke it.

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 fully describes the key parameter with 100% coverage. The description adds value by explaining the 'omit the key to list all' behavior, and reinforces the purpose of the parameter. This goes beyond simply restating the schema, earning above baseline.

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's function with specific verbs: 'Retrieve a value previously saved via remember, or list all saved keys.' It also gives concrete examples of what can be stored (ticker, address, research notes) and explicitly differentiates 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?

Provides explicit usage context: 'Use to look up context the agent stored earlier... without re-deriving it from scratch.' It also names the complementary tools to pair with (remember, forget) and explains the scoping behavior, giving the agent clear guidance on when to invoke this tool.

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