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

Annotations already signal idempotence and non-destructive behavior; the description adds scoping by identifier and retention differences between authenticated and anonymous sessions. These are material behavioral details not present in the annotations, adding significant value beyond them.

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 cover purpose, usage triggers, storage model, persistence behavior, and companion tools without redundancy. Every sentence contributes actionable information, making it highly efficient.

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 two-parameter write tool, the description covers what, when, why, persistence semantics, and relationships with related tools. With annotations covering safety and idempotence, nothing critical is missing.

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%, with both parameters clearly described and exemplified. The description doesn't add new parameter semantics beyond reinforcing the key-value nature, so the baseline score of 3 is appropriate.

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 a specific verb+resource ('Save data the agent will need to reuse later') and clearly distinguishes itself from memory siblings by naming recall and forget as partners. It leaves no ambiguity about the tool's role.

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 states exactly when to use the tool ('when you discover something worth carrying forward') with concrete examples, and gives explicit guidance on companion tools ('Pair with recall to retrieve later, forget to delete'). This is exemplary usage guidance.

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