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

Adds genuine context beyond the minimal annotations (only destructiveHint=true and a title): the mutation label, the fact that the note is internal and invisible to the contact, and the underlying POST endpoint. It does not clarify why a note-add carries destructiveHint=true or whether notes can be edited/removed, which would have closed the gap.

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 compact sentences, front-loaded with the operation type, followed by the key behavioral fact and the API mapping. No wasted text.

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 two-parameter write tool with no output schema, the description supplies the essentials: mutation semantics, visibility of the created note, and the backing endpoint. Only the destructiveHint rationale and idempotency/limits are left unexplained.

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% and both parameters are documented in-schema (contact id, note text with a 5000-char cap). The description adds no parameter-level information beyond the endpoint template, so the baseline 3 applies.

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+resource ("adds an internal note to a contact") and the WRITE prefix immediately separates it from the read-side sibling textus_list_contact_notes. An agent knows exactly what this does without opening 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?

Usage is only implied by the WRITE label and the word "adds"; there is no explicit when-to-use or when-not guidance, and the read counterpart textus_list_contact_notes is never named as the alternative for retrieving notes.

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