set_dynamic_format_string

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

With no annotations provided, the description carries the full burden of behavioral disclosure. It explains the effect (context-dependent formatting), gives examples, and clarifies the table parameter semantics. However, it does not disclose whether setting the format string overwrites an existing one, whether permissions are required, or what happens if both measure and calculationItem are provided/null. This is a moderate level of transparency for a mutation tool.

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 concise and well-structured: two sentences that state purpose, give examples, and provide usage instructions. No redundant information or fluff, and the key information is front-loaded.

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 description covers the core functionality and parameter usage but lacks important contextual details for a mutation tool without annotations. It does not mention prerequisites (e.g., measure/calculation item must already exist), potential errors, or whether the operation is destructive or reversible. The tool is moderately complex with 5 parameters, so this is a noticeable gap.

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?

The description adds value beyond the schema's parameter descriptions. It explains that 'measure' and 'calculationItem' are mutually exclusive ('Provide measure for a measure, or calculationItem...'), and clarifies that 'table' should be the measure's table or the calculation-group table. This helps disambiguate parameter usage beyond the schema's field 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 the tool's function: 'Set a dynamic (DAX-driven) format string on a measure OR a calculation item'. It uses a specific verb and resource, and explains the effect ('displayed format changes with context') with examples. This distinguishes it from sibling tools like set_custom_format_string by emphasizing the dynamic, DAX-driven nature.

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 gives clear context for when to use the tool: when a dynamic format string is needed, and it provides explicit usage instructions for the two modes ('Provide measure for a measure, or calculationItem (with its calculation-group table) for an item'). It does not explicitly mention alternatives or when not to use it, but the 'dynamic (DAX-driven)' qualifier implies the distinction from static format setters.

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