fill_up

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

With no annotations, the description carries the burden of behavioral disclosure. It discloses that the tool 'Appends Table.FillUp to the table's M query' and that columns are comma-separated, which gives useful context about the underlying operation. However, it does not disclose side effects (e.g., whether the table is modified in place, if it requires a session, or what happens when no non-null value exists).

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 two sentences, front-loaded with the core purpose and followed by a specific implementation detail (Appends Table.FillUp) and a parameter-format note. Every sentence earns its place with no unnecessary 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?

The tool has no output schema and no annotations, so the description must explain the operation and its effects. It adequately explains the fill-up mechanics and M query modification, but it does not describe return values, required session/table context, or potential edge cases. This makes it generally informative but not fully complete for an AI agent.

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 schema descriptions cover 50% (columns and partitionName), but the description adds critical value by explicitly explaining 'columns is comma-separated' and connecting it to the fill-up operation. It does not explain 'table' or 'sessionId', though these may be common across tools. The description only partially compensates for the low schema coverage.

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 uses a specific verb and resource: 'Power Query Fill Up' and 'replace nulls in a column with the most recent non-null value below'. This clearly states what the tool does and distinguishes it from the sibling tool 'fill_down' by describing the upward direction.

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 usage from the purpose (fill nulls upward) and references 'Power Query Fill Up', but it does not explicitly provide 'when to use' or 'when not to use' guidance, nor does it mention alternatives like fill_down. The context is clear but without exclusions or alternative references.

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