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

Annotations already declare destructive/non-idempotent/not-read-only, and the description adds substantially beyond that: edits merge live with concurrent typers, edit access is required, and encrypted notes are refused. These are exactly the behavioral traits an agent must know before calling a mutation tool.

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?

Four short sentences, zero filler, and the core action and mode semantics are front-loaded ahead of the access/encryption caveats. Every clause earns its place.

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 mutation tool with annotations covering the safety profile and no output schema, the description covers action, mode semantics, concurrency behavior, and preconditions. Nothing an agent needs in order to call it correctly is missing.

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 id, markdown and mode. The description's mode explanation ('adds text on a new line at the end') adds a small amount of detail beyond the schema's 'adds to the end', but it largely restates what the schema provides, warranting the baseline 3.

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 and resource ('Changes a note's markdown') and immediately defines the two operating modes, which is enough to separate it from read_note and create_note. The scope is pinned down without the agent needing to open the schema.

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?

The description explains what each mode does and the preconditions (edit access, encrypted notes refused), which implies when it is usable. However, it never states when to choose update_note over create_note or read_note, nor any when-not-to-use guidance, so the routing signal is only implied.

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