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

Annotations already declare readOnly/idempotent/non-destructive, but the description adds genuinely new behavioral facts: the OAuth scope required (orders:read) and the hard result cap of 10 most recent orders (with no paging stated). Repeating 'Read-only' is redundant but harmless; return-field disclosure is a bonus beyond the annotation set.

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 front-loaded sentences with zero waste: scope and cap first, then the auth prerequisite and safety note. Every clause earns its place, and the trailing 'Read-only.' is a trivial redundancy only.

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 field enumeration does real work in telling the agent what comes back, and the auth scope covers the main failure mode. It falls short of complete only in not stating behavior when unconnected (error vs empty) or that the 10-order cap is fixed rather than paginated.

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?

Zero parameters, so baseline is 4. The enumerated fields (litres, oil supplier, status, price, delivery window, delivered litres) describe return values rather than inputs, which is helpful given no output schema, but nothing parameter-related needs compensating.

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 (the signed-in customer's 10 most recent heating oil orders) with an explicit scope and result cap. This is clearly distinct from the sibling tools, which cover prices, supplier lookup and delivery drafting, so an agent can route correctly without opening a 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?

The prerequisite is spelled out ('needs the customer to connect their Tankful account (orders:read)'), which is useful selection context. However, there is no explicit when-to-use vs when-not guidance, nor any mention of how it relates to tankful_delivery_request_draft or what to do if the account is unconnected.

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