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

Adds substantial context beyond the annotations: the default-draft behavior, that approving triggers a ledger entry, that each call is user-confirmed by default, that the action reaches other people, and that a scoped API key is required. These are exactly the side-effect and auth details an agent needs for a mutating, open-world call.

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-loads the core action and is information-dense, but the confirmation guidance is repeated ('By default you confirm each call...' then 'Reaches other people: confirm with the user before each call'), which costs a little 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 an 8-parameter mutation with no output schema, the description covers behavior, side effects, confirmation, and auth. It is nearly complete; the only modest gap is the absence of explicit guidance on date/deduction semantics, which the schema already documents.

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%, so baseline is 3, and the description adds a real constraint not in the schema: 'Each line needs an expense account, because Holded needs one for the ledger.' It also clarifies that the number is the supplier's own document number, going beyond the field-level text.

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: 'Record a supplier bill as a purchase, as a draft or approved.' The distinction between a supplier bill/purchase and the sales-invoice sibling is implicit but clear, and the draft/approved modes are named up front.

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?

Clearly explains the draft-vs-approved choice ('With approve false, the default, the purchase is saved as a draft. Approving makes Holded create the accounting entry'), which tells the agent when to pick each mode. It does not explicitly route against a sibling tool, but the operational guidance is solid.

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