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

With no annotations provided, the description carries the full behavioral burden but discloses nothing beyond 'update'. It does not state permissions, reversibility, whether unspecified fields are preserved (partial vs full update), or overwrite semantics — critical for a multi-field mutation with six optional parameters.

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 front-loaded sentence with no filler, listing the mutable fields efficiently. Nothing is wasted, though it is perhaps too terse for a seven-parameter mutation.

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 seven-parameter mutation with no annotations, no output schema, and six optional nullable fields, the description omits the key question of partial-update semantics and side effects. The schema covers parameter meaning, but nothing explains what an update actually does to the record.

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%, so the schema already documents all seven parameters; baseline 3 applies. The description's field list loosely echoes the schema (and slightly conflates 'margin' with the 'marginType' parameter) without adding format or constraint detail.

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 ('Update') and resource ('partner surcharge') plus the mutable fields (amount, margin, VAT, carrier cost). This naturally distinguishes it from UpdatePartnerRate and UpdateCustomRate, though it never names those siblings explicitly.

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 description implies usage only through 'existing partner surcharge' and offers no when-to-use, when-not-to-use, or alternative routing (e.g., vs UpdatePartnerRate or AddPartnerSurcharge). An agent gets no guidance on choosing between the many sibling update tools.

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