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

Annotations already mark this as a non-destructive, closed-world mutation, but the description adds real behavioral context the annotations lack: per-call row cap, cumulative inline-row cap, payload size ceiling, and cost. It does not disclose failure behavior (partial append, atomicity) or what the response contains.

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?

Three short sentences, front-loaded with the action and its limit, followed by the positional-format rule and the escalation path. Every clause carries operative information; nothing is 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 two-parameter append tool with no output schema, the description covers limits, row format, and the large-volume alternative, which is nearly everything needed to call it correctly. The remaining gap is the absence of any statement about the return value or partial-success behavior.

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 coverage is only 50% — only list_id is documented, rows is not — so the description usefully specifies that rows are positional, one value per column in column order, and capped at 500. That compensates well for the undocumented rows parameter, though it doesn't say how nulls or mismatched column counts are handled.

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?

States a specific verb and resource ('Append ... rows to an inline list') plus a concrete batch ceiling of 500 rows, which separates it from read paths like get_rows and from bulk upload flows. It stops short of naming the alternative tool explicitly, so a sibling-level distinction is only implied.

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?

'use an upload for more' gives a clear alternative and the condition that selects it, and the 500-row/5,000-row/4 MB thresholds tell the agent when this tool is inappropriate. There is no guidance on prerequisites such as whether the target list must be empty, inline, or have matching columns.

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