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

With annotations only covering readOnly=false, destructive=false and openWorld=true, the description adds material behavior: notes are irreversible because 'There is no tool to delete a note', a confirmation is required per call and can be switched off, the note reaches other people, and a Cotlet API key with app access is required. These are exactly the mutation-risk, auth, and side-effect facts an agent needs before invoking.

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?

The opening two sentences restate the same fact twice ('Add a note to the Notes tab of a contact' / 'Adds a note to the Notes tab of one contact'), duplicating the title and wasting the most valuable position. The remaining sentences are dense and load-bearing, so the text is adequate rather than tight.

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 annotations and full schema coverage but no output schema, the description covers the essentials an agent cannot get from structured fields: irreversibility, per-call confirmation, human-visibility of the note, and auth requirements. It is only short of explaining what the call returns on success.

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% (both text and contact_id are documented, including the cross-reference to search_contacts), so the schema carries the parameter burden. The description adds only the implicit detail that the author is 'your name', not a supplied parameter, which is marginal added value. 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?

The description gives a specific verb and resource ('add a note to the Notes tab of one contact') and adds the scope qualifier 'under your name', which distinguishes it from a generic contact mutation in the MarketSharp family. It does not explicitly contrast with the sibling marketsharp_add_activity, so an agent must infer the note-vs-activity boundary itself.

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?

It explains the confirmation workflow ('By default you confirm each call') but never states when to choose this tool over alternatives such as add_activity, nor any prerequisites for selecting it. Usage context is implied through the confirmation policy rather than through explicit when/when-not guidance.

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