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

Annotations already declare readOnlyHint=false, idempotentHint=false and destructiveHint=false, so the agent knows this is a non-idempotent write that is not destructive. The description is consistent with that ('create or change') but adds nothing beyond it: no statement of what happens to existing content, whether a missing id creates a new notebook, or whether appends are safe to repeat.

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 front-loaded sentence with the trigger condition first and the affected fields after. No filler, though the clause list is slightly compressed into one run-on string.

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 five-parameter, no-output-schema mutation tool, the description covers the trigger and the editable fields but leaves the create-vs-update switch (the role of 'id'), the append behavior, and failure conditions unexplained. Adequate as a starting point, not complete.

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 0% across five parameters, so the description must carry the load. It does enumerate four of them (title, body, appended text, pin), which is genuine added meaning, but it omits 'id' entirely — the parameter that determines whether this creates or mutates — and never clarifies body-vs-append semantics or the length limits.

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 gives a clear verb+resource: create or change a notebook, with the mutable fields enumerated. It does not differentiate itself from the sibling journal_note or list_notes, and the name/title mismatch (write_note vs 'notebook') leaves some ambiguity about whether notes and notebooks are the same object.

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 supplies an explicit trigger — 'use this when the user wants to create a notebook or change one' — which is more than most definitions offer. However it names no alternatives (journal_note, list_notes) and gives no when-not guidance or prerequisites, so the routing decision is still left partly to inference.

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