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

Annotations already indicate read-only, idempotent, and non-destructive behavior. The description adds meaningful context beyond that: the data is scoped to the agent's identifier (anonymous IP, BYO key hash, or account ID), and omitting the key lists all saved keys. It does not describe behavior on missing keys or return format, but given annotations, this is sufficient.

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 core action, and every sentence adds value: purpose, usage guidance, and scope/alternatives. No redundancy or unnecessary verbiage.

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 purpose, usage timing, scope, and relationships to sibling tools. It implies return values ('Retrieve a value' / 'list all saved keys') and does not need to explain an output schema. Minor gaps like error behavior are acceptable given the tool's simplicity.

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 covers 100% of the parameter ('Memory key to retrieve (omit to list all keys)'), so the baseline is 3. The description repeats the omit behavior and provides examples of key values, adding some semantic context about what keys represent, but it does not add new parameter-level detail.

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 states a specific verb ('Retrieve' / 'list') and resource ('a value previously saved via remember' / 'all saved keys'), clearly distinguishing it from sibling tools like remember and forget. It also provides concrete examples ('user's target ticker, an address, prior research notes'), making the purpose unambiguous.

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 names the complementary tools ('Pair with remember to save, forget to delete'), giving clear guidance on when to use this tool vs alternatives. The scope note ('Scoped to your identifier') adds context about its applicability.

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