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

With annotations already indicating readOnlyHint=false and destructiveHint=false, the description adds the critical constraint that 'Type is immutable' and the workaround of forgetting and storing again. This is valuable behavioral context beyond the annotations, though it doesn't cover permissions or error cases.

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?

Two sentences with no wasted words. The first sentence front-loads the action and scope; the second provides a crucial exception and alternative. Perfectly concise and structured.

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?

The description covers the purpose, the key constraint, and the workflow alternative. The schema and output schema handle parameter and return details, so the description is complete for an update tool of this simplicity.

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?

The schema covers all parameters with 100% description coverage, so the baseline is 3. The description adds meaning by explaining why there is no type parameter (immutability) and by summarizing the updatable fields (name, description, or content), which aligns with the schema and adds a note about the immutable type.

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 verb and resource: 'Update an existing memory's name, description, or content.' It distinguishes from sibling tools like store_memory (create new) and forget_memory (delete) by focusing on updating an existing 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?

It explicitly provides the alternative for reclassification: 'Type is immutable; to reclassify, forget and store again.' This tells the agent when not to use this tool and what to use instead, making the usage context clear.

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