pbi_run_dax

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

The description discloses rich behavioral detail beyond the annotations: fail-closed grammar enforcement, result truncation reasons (rows vs size), the export side effect writing to outputs/, and passthrough of DAX engine errors. This gives the agent a precise model of what the tool will and will not do, and it is consistent with the annotations.

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 front-loaded with the core purpose, then covers constraints, parameters, return behavior, and an example without wasted sentences. Each sentence adds operational value, and the structure is easy for an agent to scan.

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 5-parameter query tool, the description is complete: it defines the target model, accepted query grammar, fail-closed behavior, result limits, export option, return contents, error handling, and an example invocation. The existence of an output schema further reduces the need to document return structure in prose.

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 0%, but the description compensates fully: it explains query's mandatory role and no-alias rule, max_rows, max_bytes, timeout_seconds, and export's side effect of writing to outputs/ and returning the path. Every parameter receives meaningful semantics.

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 states a specific verb and resource: it executes a read-only DAX query against the active model. It clearly distinguishes this from the many sibling tools by specifying the query nature, the accepted DAX forms, and the fail-closed behavior.

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 usage context: use it for read-only DAX against the active model, and explicitly excludes anything that is not EVALUATE, DEFINE...EVALUATE, or $SYSTEM DMVs. It does not name alternative sibling tools, so it stops short of a 5.

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