update_price_rule

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

No annotations are provided, so the description carries the full burden. It discloses the mutating effect ('modifies the price rule'), specifies partial-update semantics ('Only provided fields are updated'), and adds a constraint that 'value must remain a string if updating.' These go beyond what the input schema alone conveys and help the agent understand non-obvious behavior.

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?

The description is short but contains redundancy: 'Update an existing price rule' and 'Side effect: modifies the price rule' essentially repeat the same idea. The note about 'value' is placed awkwardly at the end. While it is front-loaded with the purpose, the redundant sentence reduces overall clarity.

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 8 parameters fully documented in the schema and no output schema, the description covers the key behavioral aspects: targeting an existing rule, partial updates, and the value type constraint. It doesn't mention return values, but that would be standard for an update operation and is not required here.

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 the baseline is 3. The description adds value by clarifying that only provided fields are updated (partial update), which affects how parameters should be interpreted, and explicitly notes that the 'value' parameter must remain a string—a detail not fully emphasized in the schema descriptions.

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?

The description clearly states 'Update an existing price rule,' identifying the action (update) and resource (price rule). This distinguishes it from sibling tools like create_price_rule, get_price_rule, and list_price_rules, as the verb and 'existing' scope are explicitly different.

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 the tool is for updating already-created price rules via the word 'existing,' and notes that only provided fields are updated. However, it does not explicitly mention when to use this versus alternatives (e.g., create_price_rule for new rules) or provide any exclusions, so guidance is implied rather than explicit.

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