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

Annotations already declare readOnlyHint=true, openWorldHint=false and destructiveHint=false, so safety is covered. The description still adds real behavioral value beyond them: the null-on-missing return contract and the deliberate indistinguishability of a wrong-owner id from a missing one, which tells the caller not to probe for existence across users.

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?

Three short sentences, front-loaded with the operation, then the safety note, then the return contract. No filler; every sentence conveys something an agent needs.

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 one-parameter read with no output schema, the description covers what it does, that it is read-only, and what comes back on miss. The only gap is the accepted id form (integer vs string), which the schema leaves bare.

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 0% for the single note_id parameter, so the description must carry the load. 'By id' and the note on wrong-owner ids add some meaning about scoping, but nothing explains that note_id accepts either an integer or a string, which is the one non-obvious thing about the parameter.

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?

Specific verb+resource+scope: 'Read a single personal note by id from the caller's workspace.' An agent can tell this is a single-item read, not a list or a write. It does not name a sibling (e.g. get_meeting_note, create_note) to sharpen the boundary, keeping it at 4.

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: use it when you have an id and want one note. There is no explicit statement of when to prefer another tool or what to do if you only have a title/owner, and no prerequisites are stated.

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