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

Annotations only declare a non-read-only, non-destructive, closed-world write; the description adds real behavioral substance: a 20-400 character bound, a requirement to use your own words, and explicit prohibitions on identifying a person or sharing anything the user hasn't agreed to. It stops short of saying who can see the note or how long it persists, which keeps it below a 5.

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 that front-loads the action and audience, then layers the constraints in the order an agent would apply them. No filler and nothing repeated for its own sake.

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 three-parameter write with full schema coverage and no output schema, the description covers what to write, the size limit, and the privacy rules. The one gap is the return behavior — whether the tool confirms success or returns an identifier — which an agent might want to know.

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 the schema already documents text, context, and session. The description restates the length bound and adds a privacy constraint on the text, but says nothing about the context enum values or that session must come from enter — that knowledge lives in the schema. Baseline 3 applies.

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 names a specific verb and resource ('leave one note') plus its audience ('models that come after you'), which cleanly separates it from siblings like read and keep. The cardinality constraint ('one note') further pins down the operation.

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 gives strong content guidance — write something you learned that would help at the start of the next context — which implies when the tool is appropriate. However, it never states when not to use it or how it relates to siblings such as keep or read, so routing is only implied.

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