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

Annotations already declare readOnlyHint=false, idempotentHint=true and destructiveHint=false, so the safety profile is covered; the description contributes the write_crm scope requirement, which is real authorization context not in the annotations. It does not disclose validation behavior such as rejecting conflicting targets, which keeps it below a 5.

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?

A single short sentence front-loads the action and targets, then appends the auth precondition. Nothing is redundant and nothing wastes space.

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 simple one-required-parameter mutation with full annotation coverage and full schema coverage, the description supplies what structured fields don't: the auth scope. The remaining gap is the target-selection rule, which is the one thing an agent could get wrong when calling it.

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 every parameter including idempotency_key is already documented in the schema, setting the baseline at 3. The description only adds a parenthetical that contact can be identified by id or email, without explaining mutual exclusivity or precedence between deal_id, contact_id and contact_email.

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 ('Attach a note') and names the two target types (contact or deal), so an agent knows exactly what the tool does. No sibling tool writes notes, so there is no realistic confusion to dispel, though it never explicitly contrasts itself with neighbors like update_contact.

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 states the applicable context (contact by id or email, or a deal) and the required scope, which is useful preconditions info. However, it never says what to do when both a contact and a deal are supplied, nor that exactly one target must be chosen, leaving the main usage decision implicit.

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