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

No annotations are supplied, so the description carries the full burden. It does disclose the authentication requirement (secret edit key from save_note) and that one mode overwrites existing content, which is meaningful behavioral context, but it says nothing about what happens with an invalid key, whether replacement is recoverable, or what the tool returns.

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 short sentences with zero filler; the action is front-loaded and the prerequisite follows. Nothing is redundant or buried.

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 mutation tool with no annotations, no output schema, and half its parameters undocumented, this is under-specified. An agent cannot tell what 'id' is, how replacement interacts with existing content, or what a successful edit yields, so the definition is not complete enough for safe invocation.

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 only 50%: 'key' and 'append' are already documented in the schema, and the description only restates the key requirement and the replace/append choice. The undocumented parameters 'id' and 'text' receive no explanation at all (e.g., whether id is the note identifier, whether text may be empty).

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 pair ('Replace or append') against a specific resource ('a saved note'), so an agent knows exactly what action is taken. It implicitly separates itself from save_note by requiring that note's key, but never names read_note or other siblings for viewing existing notes.

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 sentence 'Needs the key from save_note' gives a clear prerequisite and implies this tool is only for notes that already exist. There is no explicit statement of when not to use it (e.g., creating a new note -> save_note) or how it relates to read_note.

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