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

Annotations already declare this is a non-read-only, non-destructive, non-idempotent, closed-world write. The description adds genuinely non-obvious behavior: no change occurs until a human approves the exact request in Settings > MCP and execute_approved_action is called, and approval requirements are admin-configurable. That is exactly the kind of gating detail annotations cannot convey.

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?

Four short sentences, front-loaded with the record context and the core action, followed by the approval caveat. No filler, though the opening 'when working with ... records' sentence is somewhat boilerplate.

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 mutation tool with ~24 nested fields documentable nowhere but the schema, and an output schema that handles return values, the approval-workflow explanation is strong. The complete absence of parameter guidance is the remaining material gap.

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 0% across a nested `data` object with ~22 fields (itemName required, carrier enum, cost pattern, date formats, UUID siteId), and the description supplies no field meaning, units, or defaults. Only the phrase 'a site's purchase list' weakly hints that siteId is the target site; the rest of the payload is undocumented in both places.

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 an item to a site's purchase list,' which is distinct from add_purchase_template_item (templates) and update_purchase_item. It does not explicitly name or contrast with those nearest siblings, so the differentiation must be inferred from the site-scoped wording.

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?

'Use this when working with RetailHardHat purchase_lists records' gives a context, and the approval sentence implies a prerequisite workflow. However, it never states when to prefer create_purchase_item over add_purchase_template_item or apply_purchase_template, nor any exclusions.

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