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

With readOnlyHint and destructiveHint annotations already declaring a safe read operation, the description adds valuable context: it explains the dual behavior (retrieve vs list), scoping to the agent's identifier (IP, key hash, or account ID), and the omission-to-list-mode. However, it doesn't disclose behavior for missing keys or pagination, though those are minor.

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, each packed with relevant information. The first sentence states the main action and both modes, the second gives a concrete use case, and the third adds scoping and complementary tools. No filler or redundant 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 simple tool with one optional parameter, no output schema, and strong annotations, the description fully covers the two usage modes, scoping behavior, and relationship to sibling tools. There is no missing context that an agent would need to invoke it 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 provides 100% coverage for the single key parameter, so the baseline is 3. The description enriches this by explaining the key is for retrieving a single value while omitting it lists all keys, and gives concrete examples of what keys might represent (target ticker, address, research notes), adding practical meaning.

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 explicitly states the tool retrieves values previously saved via remember or lists all saved keys, with a clear verb-resource pairing. It differentiates itself from related tools by naming remember and forget as the complementary save/delete counterparts.

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?

It provides a specific use case: looking up previously stored context like a ticker, address, or research notes without re-deriving it. It also implicitly advises when to use this tool (when context was saved earlier) and when not to (re-deriving), plus names the complementary tools remember and forget.

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