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

Annotations already declare readOnlyHint=true and idempotentHint=true, so safety is covered. The description adds scoping context: 'Scoped to your identifier (anonymous IP, BYO key hash, or account ID),' which is meaningful beyond annotations. No contradiction.

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 function, includes usage context, scoping, and pairing information without redundancy.

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 1-parameter read-only tool with full annotation coverage, the description covers function, usage scenarios, scoping, and related operations. No output schema needed since the return type is implicit (value or list of keys).

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 describes the single parameter 'key' completely (100% coverage), giving baseline 3. The description enriches it with concrete examples of what keys may contain ('user's target ticker, an address, prior research notes') and reinforces the omit-to-list behavior.

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 uses specific verbs 'retrieve' and 'list' and clearly identifies the resource: values saved via remember. It distinguishes from sibling tools remember and forget by naming them, and from broader research tools with 'without re-deriving it from scratch.'

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 states when to use: 'Use to look up context the agent stored earlier... without re-deriving it from scratch.' It also provides guidance on alternatives: 'Pair with remember to save, forget to delete,' and the optional key argument clarifies the two usage modes.

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