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

Annotations already indicate non-read-only, non-destructive, and idempotent behavior. The description adds valuable context beyond annotations: key-value scope by identifier, 24-hour retention for anonymous sessions, and persistent memory for authenticated users. It does not contradict annotations and provides extra details about data lifecycle, though it stops short of explaining overwrite behavior or failure modes.

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 sentences, front-loaded with the main action and purpose, followed by usage context and pairing information. Every sentence contributes unique value with no redundancy or filler.

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 tool with no output schema, the description covers purpose, usage scenarios, persistence, and companion tools. It is complete enough for an agent to select and invoke correctly, though it leaves minor edge-case behaviors (like overwriting existing keys) unspecified, which is acceptable given the annotations and schema richness.

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 both 'key' and 'value' having descriptive examples. The description reinforces the parameter roles by illustrating typical keys and values, but does not add substantial new meaning beyond the schema. Thus 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 clearly states the tool's function with a specific verb ('Save') and resource ('data the agent will need to reuse later'), and it distinguishes from sibling tools by naming the paired operations (recall, forget). Concrete examples of use cases (resolved ticker, target address, user preference) further ground the purpose.

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 guidance ('Use when you discover something worth carrying forward') and differentiates contexts (authenticated vs. anonymous sessions, cross-conversation vs. cross-sessions). It alludes to alternatives by mentioning 'Pair with recall to retrieve later, forget to delete,' but does not explicitly state when not to use the tool.

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