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

Annotations already flag mutation and non-idempotency; the description goes further, disclosing cross-session persistence, cross-assistant visibility, the returned fields (memory ID, source, type, autolinked IDs), and the duplicate-on-retry risk. That is exactly the operational context an agent needs before a write call.

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?

Front-loaded with the action and its trigger, then constraints, then return values — a sensible order with no filler. It runs six sentences, and the return-value sentence partially duplicates what a caller could infer, so it is dense rather than perfectly trimmed.

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?

A mutation tool with no output schema, yet the description covers the trigger, exclusions, persistence model, return payload, and retry hazard. Nothing material is missing for an agent to call it correctly.

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%, so baseline is 3, but the description adds real meaning: it clarifies that saving creates links and can duplicate on retry, and that tags are labels not permissions. It largely restates rather than extending type/source semantics, keeping it short of a 5.

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?

States a specific verb (Save) plus the exact resource (a distilled fact, preference, decision, idea or note) and the destination (the authenticated user's STEM account). It also names what it does not do (read/import conversations, browse the web, access other users' data), which separates it cleanly from recall, forget and remember_automatically.

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?

Gives a crisp trigger — 'when the user explicitly asks to remember it' — implied contrast with the automatic sibling, plus hard exclusions ('Do not store whole transcripts or secrets'). It never explicitly names remember_automatically as the alternative path, so routing between the two still requires inference.

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