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

Annotations already declare readOnlyHint=false, destructiveHint=true, idempotentHint=false and openWorldHint=true, so the safety profile is largely covered. The description still adds a genuinely non-structured behavioral fact: the note is internal and never customer-visible, plus the underlying endpoint. It omits permission requirements and whether retries create duplicates (relevant given idempotentHint=false).

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 tightly written sentence with the WRITE cue front-loaded. The trailing "POST /order-notes" is redundant for an agent that invokes the tool through MCP rather than raw HTTP, which is the only wasted token.

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 full schema coverage, no output schema, and annotations that already carry the safety profile, the description covers what matters: what is created and who can see it. It stops short of stating auth needs or side effects on the parent order.

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 (with length bounds) and sales_order_id (with positivity bound) are documented in the schema. The description adds no syntax, formatting, or content guidance beyond that, 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?

Names a specific verb (add), resource (note), and target (a sales order), which separates it cleanly from the sibling edesk_add_ticket_note and from the read-only edesk_list_order_notes. The parenthetical "never sent to the customer" further pins down the artifact being created.

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: the phrase "internal note … never sent to the customer" hints this is for private annotation rather than customer-facing communication, but the description never states when to choose this over edesk_add_ticket_note, edesk_reply_to_ticket, or edesk_update_ticket. No prerequisites or exclusions are given.

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