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

Annotations already declare readOnlyHint=true, destructiveHint=false, so the safety profile is covered. The description adds real behavioral context beyond that: conditional field presence (due date only for invoices), that publishing errors are surfaced when a publish failed, and an explicit auth/key requirement. It does not cover throttling or error/empty-result behavior, hence not 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?

Front-loaded with the core purpose ('One item with all extracted fields...') and then elaborates on returns, conditionals and auth. The field enumeration is a long list but each entry conveys return content; only mild redundancy in restating that it mirrors the 'Item details page' before listing those same fields.

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?

With no output schema, the description takes on the full burden of describing returns and does so thoroughly, including conditional fields (due date for invoices) and error surfaced (failed publishes), plus the auth requirement. Nothing an agent needs to call a single-item getter correctly appears missing.

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 coverage is 100% and the single item_id is already documented in the schema ('Item ID from list_items'). The description adds no parameter-level meaning beyond that, so the baseline 3 for fully-covered schemas 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?

States a specific verb and resource ('Get item') and goes further by enumerating the returned fields (supplier, date, total, publish state, etc.), so the agent knows exactly what the call produces. It clearly contrasts with list-style siblings by returning 'one item', but it never names or explicitly distinguishes itself from dext_get_item_history or dext_update_item.

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: fetch a single item's details given an ID. There is no when-to-use/when-not-to-use guidance and no pointer to alternatives (e.g., list_items for collections, get_item_history for audit trails). The auth note ('Needs the user's Cotlet API key with access to this app') is a prerequisite, not selection guidance.

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