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

The description adds behavioral context beyond annotations: persistence semantics are disclosed ('Authenticated users get persistent memory; anonymous sessions retain memory for 24 hours'), and it explains scoping by identifier and key-value storage. It does not contradict the annotations (readOnlyHint=false, idempotentHint=true), and the retention policy is genuinely useful operational information.

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 tightly written with three sentences, each contributing distinct value: purpose, usage examples, and retention/pairing details. It is front-loaded with the primary action, and no filler or redundant wording is present.

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 write operation with two parameters and no output schema, the description fully covers what the tool does, when to use it, persistence rules, and how it relates to recall and forget. It is complete enough for an agent to select and invoke the tool correctly without ambiguity.

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% with already descriptive parameter descriptions (e.g., 'Memory key (e.g., "subject_property")'). The description reinforces the key-value pairing but does not add substantial new meaning beyond the schema. It mentions 'scoped by your identifier' which touches on key namespace, but this is more behavioral context than parameter semantics, so a 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 opens with a specific action: 'Save data the agent will need to reuse later,' clearly identifying the verb and resource. It also distinguishes from siblings by stating 'Pair with recall to retrieve later, forget to delete,' which differentiates it from recall and forget. The scope (across conversations and sessions) adds precision.

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?

Explicit usage conditions are provided: 'Use when you discover something worth carrying forward' with concrete examples like 'a resolved ticker, a target address, a user preference, a research subject.' It also gives complementary guidance on when to use recall (retrieve) and forget (delete), thereby covering alternatives within the tool family.

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