Update Budget Line Item

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

Annotations already indicate mutation (readOnlyHint=false) and non-destructive (destructiveHint=false). Description adds 'returns the modified object on success' and API endpoint details. It does not disclose side effects, validation behavior, or error handling beyond what annotations imply. The bar is lowered due to annotations, but description still adds modest value.

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?

Four sentences capture action, usage context, partial update behavior, return value, required parameters, and API version. All information is front-loaded and essential. No unnecessary words.

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?

The tool has a complex nested parameter (budget_line_item) with no schema definition for its properties, and no output schema. The description does not specify what fields the object can contain, validation rules, or response structure. For an agent to correctly invoke this tool, more information about the budget_line_item object is needed.

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 has 100% description coverage, but each description is minimal (e.g., 'URL path parameter — unique identifier of the Budget resource'). The tool description lists required parameters but does not explain the 'budget_line_item' object's allowed fields or structure. Baseline 3 is appropriate; description adds no extra semantic depth.

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 explicitly states 'Update a line item of a specified budget' and distinguishes from creation (create_budget_line_item) by focusing on updating existing records. The verb 'update' and resource 'budget line item' are clear, and the phrasing 'only the supplied fields are changed' clarifies partial update semantics.

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 says 'Use this to update an existing Budget records,' indicating the context (existing records). It does not explicitly exclude creation or list alternatives, but given sibling tool names (create_budget_line_item), the distinction is implicit. No misleading guidance.

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