merge_columns

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

The description discloses important behavioral traits: it warns that 'the source columns are consumed' and that it 'Appends Table.CombineColumns ... to the table's M query.' These are meaningful side effects, especially since no annotations are provided. However, it does not mention reversibility, failure modes, or permission requirements.

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 extremely concise, consisting of two sentences that are front-loaded with the primary purpose. The second sentence adds implementation and side-effect details without unnecessary verbosity.

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 mutation tool with no annotations or output schema, the description covers the core operation and a key side effect, but it omits details about return values, prerequisites, and the exact meaning of the 'table' parameter. It is adequate for simple use but not thoroughly complete.

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 one key detail for the 'columns' parameter (source columns are consumed), but repeats the comma-separated property already in the schema. It does not clarify the 'sessionId' or 'table' parameters, which lack schema descriptions. With 67% schema coverage, the description provides marginal additional meaning.

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 operation: 'concatenate two or more columns into one new column with a separator.' It is specific about the resource (columns) and the verb (concatenate/merge), and it distinguishes from sibling tools like merge_queries by focusing on columns rather than queries.

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 implies when to use the tool (when you need to merge columns in Power Query) but does not explicitly state usage conditions or alternatives. It lacks guidance on when not to use it or how it compares to similar tools like concatenate_with_group_by.

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