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

Annotations already declare readOnlyHint=false, idempotentHint=true, and destructiveHint=false, so safety is covered. The description adds real value beyond that: the default namespace ('notes'), auto-keying, and the ttl bounds (min 60, max 30 days) with auto-eviction. It omits what happens when the target key already exists, which is the key idempotency question.

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?

A single dense sentence set that front-loads the action and endpoint before the required fields and the shortcut. No filler; every clause carries information.

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 7-parameter mutation tool with no output schema, the description covers the main path well but never addresses overwrite semantics for an existing key or what 'handle'/'secret' are for. Annotations cover the safety profile, so the remaining gaps are moderate rather than severe.

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?

Description clarifies the interaction between the 'text' shortcut and the namespace/key/value trio, including the default namespace and auto-key behavior, which the schema only partially conveys. The unrelated 'handle' and 'secret' parameters are undocumented in both schema and description, leaving a genuine gap.

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+resource ('persist a value across your instances') and even names the underlying route PUT /memory/{ns}/{key}, so the agent knows exactly what operation occurs. It does not, however, explicitly distinguish itself from close siblings such as memory_retain, store_artifact, or share_memory.

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?

Usage is implied through the required-field list and the 'text shortcut' path, which tells the agent two ways to call it and the defaults each triggers. There is no explicit when-to-use-this-instead-of-a-sibling guidance, which matters given the crowded memory/artifact sibling set.

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