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

Annotations already mark this as readOnly=false, destructive=false, idempotent=false and openWorld=true, so the safety profile is covered; the description goes further and discloses note visibility to other ChurchSuite users, the private_to_me exception, that no message is sent to the contact, and that no edit/delete side effects occur. That's substantive behavioral context beyond the structured hints.

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 tight sentences, front-loaded with the WRITE classification and the core action, with supporting caveats and the endpoint in the same breath. Slight redundancy in restating private_to_me semantics already documented in the schema keeps it from being maximally economical.

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 4-parameter mutation tool with no output schema, the description covers operation class, side-effect boundaries, visibility semantics, and the underlying endpoint. It omits what the call returns (e.g., the created note or its id) and any permission prerequisite, which would be the remaining gaps for an agent.

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 the baseline is 3; the description adds real meaning for private_to_me by framing it as visibility to other users versus only the API user, which is the consequence an agent needs to reason about before setting the flag. It adds nothing extra for content, contact_id, or pinned, so it sits modestly above baseline.

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 and resource ('add a new note to a contact's record') and prefixes it with 'WRITE:' so the operation class is unambiguous. An agent can immediately distinguish this from the read-side sibling churchsuite_list_contact_notes without opening either 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?

'Only adds a note: never edits or deletes anything, sends nothing to the contact' clearly bounds when this tool is and isn't the right choice, which is the main routing risk for a note-creation tool. It stops short of naming an explicit alternative (e.g., use list_contact_notes to read existing notes), so it's strong context rather than a full when/when-not/alternative triad.

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