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

Annotations already declare the tool as read-only, non-destructive, and idempotent. The description adds valuable context beyond this: the scoping to an identifier (anonymous IP, BYO key hash, or account ID) and the behavior of listing all keys when the key is omitted. No contradiction with annotations.

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 compact and front-loaded with the core functionality. Each sentence earns its place: core function, use case, scoping, and sibling relationship. No wasted words.

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 the two modes, the scoping, and the relationship to remember/forget. It doesn't specify error behavior for a missing key or the exact list format, but those are minor gaps given the low complexity.

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 covers the key parameter, including its meaning and that omitting it lists all keys (100% coverage). The description enriches this with concrete examples of key types (ticker, address, notes) and clarifies the scoping semantics, adding value beyond the schema.

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 what the tool does: retrieve a value saved via remember, or list all saved keys when the key argument is omitted. It distinguishes the tool from siblings by explicitly mentioning remember and forget as its companion tools, and provides concrete examples of stored context (target ticker, address, notes).

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 says to use this tool to look up context the agent stored earlier, avoiding re-derivation from scratch. It also tells how to pair with remember to save and forget to delete. However, it doesn't explicitly state when not to use it (e.g., if the value is already in the current context), so it's clear but not exhaustive.

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