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

Annotations already establish read-only, idempotent, non-destructive behavior. The description adds valuable scoping context ('Scoped to your identifier (anonymous IP, BYO key hash, or account ID)') and lifecycle pairing, going beyond the structured hints.

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 dense sentences, front-loaded with the primary action, followed by use-case, scoping, and lifecycle guidance. No redundant wording.

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?

Covers both operational modes (retrieving a specific key vs listing all keys), scope, and related tools. Lacks return format details, but for a simple read tool with no output schema, the description is sufficient.

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 coverage is 100% and already explains the key parameter. The description enhances semantics with concrete key examples (user's target ticker, address, research notes), helping the agent infer appropriate key values.

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 opens with a specific verb-resource pair: 'Retrieve a value previously saved via remember, or list all saved keys (omit the key argument).' It clearly differentiates from sibling tools by explicitly naming remember and forget, and provides concrete examples of stored keys.

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 an explicit use case: 'Use to look up context the agent stored earlier... without re-deriving it from scratch.' It also names complementary tools: 'Pair with remember to save, forget to delete,' giving the agent clear decision criteria on when to use this tool.

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