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

Beyond the readOnlyHint and destructiveHint annotations, the description adds key behavioral details: the tool is scoped to the caller's identifier (anonymous IP, BYO key hash, or account ID), and omitting the key lists all saved keys. This gives the agent a fuller understanding of the tool's runtime behavior.

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 concise sentences, front-loaded with the core action. The second sentence explains a representative use case, and the third covers scoping and sibling tools. No filler or redundant phrases.

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 one-parameter read-only tool with good annotations, the description is complete. It explains what the tool does, how the optional parameter changes behavior, scope, and relationship to remember/forget, making it sufficient 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?

The schema already fully describes the only parameter (key) with 100% coverage, including the behavior of omitting it. The tool description reinforces this but adds no new semantic information beyond the schema, so a 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 clearly states the tool's purpose: retrieve a saved value via remember, or list all saved keys when key is omitted. It uses a specific verb ('Retrieve') and resource ('value previously saved via remember'), and distinguishes itself from siblings by naming 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?

Explicitly says when to use: to look up context the agent stored earlier without re-deriving it. It also tells how it pairs with remember (save) and forget (delete), providing clear alternative guidance for sibling tools.

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