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

readOnlyHint=true already tells the agent this is a safe read, so the description's main burden is lighter. It adds the underlying REST endpoint and the fact that notes are user-authored, but says nothing about ordering, result volume, or pagination behavior beyond what the schema's cursor field already declares.

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 the purpose front-loaded and zero filler. The API endpoint reference is marginally redundant but serves as a useful cross-reference, so it doesn't hurt much.

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?

This is a simple two-parameter read tool with full schema coverage, a read-only annotation, and no output schema, so the description doesn't need to explain return values. It covers what the tool does and where it maps in the API, leaving only minor gaps around result shape and pagination expectations.

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 both 'contact' and 'cursor' are already documented, including the pagination semantics in the cursor field. The description adds no parameter-level meaning beyond the schema, which is the expected baseline 3 here.

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 uses a specific verb ('List') plus the resource ('notes users wrote about a contact'), so an agent knows it retrieves contact notes. It doesn't explicitly separate itself from textus_add_contact_note, but the read/list framing makes the distinction fairly obvious.

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 phrase 'about a contact' implies the tool requires a contact in hand, so usage context is inferable. However, there is no explicit when-to-use/when-not, no mention of how this differs from textus_get_contact or textus_get_conversation_timeline, and no prerequisite guidance.

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