set_calc_group_selection_expressions

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

With no annotations provided, the description must carry the behavioral burden. It discloses an important side effect: 'auto-bumped, reported back' regarding compatibility level. However, it does not mention whether existing expressions are overwritten, whether the operation is reversible, or any permission requirements. This is adequate but not rich.

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 a single concise sentence that front-loads the action and resource, then adds the key prerequisite and behavioral note. No redundant words, no filler.

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 tool with 6 parameters (2 required), no output schema, and no annotations, the description gives a clear purpose and the compatibility constraint, but it omits how to identify the calculation group (likely via the table parameter), the exact effect of setting null values, and what 'reported back' means. The description is reasonably complete for an expert but leaves some gaps.

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 67% (4 of 6 params described). The description adds context to the parameters by explaining the NoSelectionExpression and MultipleOrEmptySelectionExpression concepts and noting optional dynamic format strings. However, it does not illuminate the required sessionId/table parameters, and the schema descriptions already cover the optional ones well, so the extra value is limited.

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 a specific verb 'Set' and a specific resource: 'a calculation group's NoSelectionExpression and/or MultipleOrEmptySelectionExpression'. It further explains what these expressions are ('the DAX returned when no / multiple calc items are selected'), which distinguishes it from other calc-group tools like set_calc_group_precedence or set_calc_item_ordinal.

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 provides clear context for when this tool is relevant (setting expressions for no/multiple selection states) and a critical prerequisite ('Needs compatibility level 1605+'), but it does not explicitly mention alternative tools or when not to use this tool. Still, the guidance is clear enough for an experienced agent.

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