Memory Update

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

With no annotations, the description carries the behavioral burden and does well: it discloses that the id is preserved, references remain valid, and an unknown id raises rather than silently creating a new chunk. It does not cover permission requirements or all side effects, but it provides meaningful error and identity behavior beyond the schema.

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 short sentences with zero waste, front-loads the core update behavior, and then explains the two most important behavioral consequences: id stability and unknown-id errors.

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?

Given 100% schema coverage and an output schema, the description does not need to explain parameters or return values. It complements those structured fields with the key mutation semantics: in-place update, id preservation, and error on unknown id. It could be slightly more complete by clarifying when to use this versus memory_add, but it is otherwise sufficient.

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 description coverage is 100%, so the schema already documents all four parameters thoroughly, including embedding recomputation and metadata merge/replace behavior. The description adds no additional parameter semantics beyond the schema, so the baseline 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 states a specific verb and resource: update an existing memory chunk in place. The phrase 'existing' and 'id is kept' helps distinguish it from memory_add, though it does not explicitly name sibling tools or contrast against memory_search/memory_forget.

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 by 'update an existing memory chunk' and the failure behavior for unknown ids, but the description does not explicitly say when to use this versus memory_add or other siblings. It gives enough context to infer the tool's role but leaves alternative selection unstated.

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