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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, establishing a safe read operation. The description adds valuable context beyond annotations: 'Scoped to your identifier (anonymous IP, BYO key hash, or account ID)' and the ability to list all keys by omitting the key. This provides behavioral nuance about data isolation and default output, though it doesn't cover error cases or empty results.

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 two sentences with no filler. It front-loads the primary function, then gives a concrete use case and scoping detail, and finally points to companion tools. Every clause serves a distinct purpose.

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 tool with strong annotations, the description covers purpose, usage context, scoping, and relationship to siblings. It is sufficiently complete without needing return-format details since no output schema exists. The description provides all necessary information for an agent to select and invoke this tool 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?

Schema description coverage is 100% for the 'key' parameter, so the baseline is 3. The description adds semantic value by explaining that omitting the key lists all saved keys, which is not explicit in the schema. This extra instruction enriches the parameter 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 clearly states the tool's action: 'Retrieve a value previously saved via remember, or list all saved keys (omit the key argument).' It specifies the resource (saved memory) and verb (retrieve/list), and distinguishes from sibling tools by explicitly referencing remember and forget as companions.

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 provides a clear use case: 'Use to look up context the agent stored earlier — the user's target ticker, an address, prior research notes — without re-deriving it from scratch.' It also names alternatives (remember to save, forget to delete), giving explicit pairing guidance. This meets the 'when and with what' bar.

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