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

readOnlyHint=true already covers the safety profile, and the description adds real behavioral context beyond it: the count is derived from totalResponses via GET /forms/{formId}/submissions with limit=1, which tells the agent this is a cheap, non-fetching operation. It doesn't discuss pagination or rate limits, but for a read-only count that is a minor gap.

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?

Two tight sentences: the purpose and filter-parity claim lead, followed by use-case examples and one implementation detail. No sentence is redundant or padding.

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?

With no output schema, the description compensates by naming the return value (totalResponses) and explaining how it is obtained, and it enumerates the filtering dimensions. It could still say what happens when zero submissions match, but an agent has enough to call this correctly.

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 100%, so every parameter (formId, search, status, afterDate, beforeDate, includePreview) is already documented, and the description only summarizes the filter set at a high level. Per the baseline rule, 3 is correct when the schema does the heavy lifting.

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 (count) and resource (a form's submissions) and immediately distinguishes it from the sibling fillout_list_submissions by noting it does so 'without pulling the answers'. An agent can tell the two apart without opening either schema.

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?

Gives concrete invocation contexts ('how many responses this week?', 'how many partial submissions?') and frames the filter parity with fillout_list_submissions, which steers selection between the two. It does not explicitly state the inverse condition (use list when you need the actual answers), so it stops just short of a full when/when-not rule.

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