update_calculation_item

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

No annotations are provided, so the description must disclose behavior. It does so by explaining that omitted properties are left unchanged and that an empty format string clears the format. However, it does not describe return values, error conditions, or side effects beyond the mutation.

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?

One compact sentence that front-loads the action and resource, then lists the updateable fields and a key behavioral note. No wasted 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?

Lacks output/return information and explicit alternatives, which would be useful given no output schema and no annotations. The partial update and clearing behavior are useful, but the description is not exhaustive.

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 covers 86% of parameter descriptions, and the description adds a key global semantic: omitted properties are unchanged. It also reiterates which parameters correspond to the updateable fields, reinforcing the mapping from description to schema.

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?

Clearly states the tool updates an existing calculation item and enumerates the editable fields (DAX expression, ordinal, format string, rename). This distinguishes it from sibling tools like set_calc_item_ordinal or set_dynamic_format_string, which target single attributes.

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?

Provides clear context: it's a partial update tool where omitted properties are unchanged. This implies usage for updating one or more fields at once, but it does not explicitly exclude alternatives like set_calc_item_ordinal for single-field updates.

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