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

Annotations declare readOnlyHint=false, idempotentHint=true, destructiveHint=false. The description adds valuable context beyond these hints, such as scoping ('scoped by your identifier') and persistence behavior ('Authenticated users get persistent memory; anonymous sessions retain memory for 24 hours'). 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 three well-structured sentences, front-loaded with the core purpose, then usage guidance, then technical context and companion tools. Every sentence adds information; no fluff or repetition.

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?

This is a simple two-parameter tool with no output schema. The description fully covers the operation's context: when to use, persistence and auth behavior, identifier scoping, and how it fits with related tools. No additional information seems necessary.

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% description coverage for both parameters ('Memory key' and 'Value to store'), so the baseline is 3. The description adds minor context by giving examples in the main text and explaining the key-value pair scope, but it doesn't add significant meaning beyond what the parameter descriptions already convey.

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 states a specific verb ('Save data') and resource ('data the agent will need to reuse later'), making the tool's purpose clear. It also distinguishes itself from siblings by explicitly mentioning companions: 'Pair with recall to retrieve later, forget to delete.' This clearly positions the tool within the memory family.

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 explicit when-to-use context: 'Use when you discover something worth carrying forward' and gives concrete examples such as 'a resolved ticker, a target address, a user preference.' It also names alternatives and complementary actions ('recall', 'forget'), fulfilling the usage guidelines dimension.

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