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

Annotations declare destructiveHint=true, so the safety profile is already carried; the description adds the genuinely useful partial-update semantics ('Only the fields you pass are changed'), which tempers the destructive expectation. It omits irreversibility and permission/encryption requirements, but the partial-update clarification is real value beyond 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?

Two tight sentences with the primary mutation front-loaded, followed by the partial-update constraint and the API endpoint. No filler; every clause carries information.

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 full schema coverage and no output schema, the description covers the operation, the partial-update behavior, the read/unread side effect, and where to get field IDs. Auth/permission requirements and the effect of the encryption password are left to the schema, which is a minor gap.

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 the schema already documents all four parameters in detail (including the read toggle, field value shapes, and the encryption password header). The description only restates read/unread and adds no syntax beyond the schema, so the baseline 3 applies.

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 ('Change field values on an existing submission') plus a secondary operation (mark read/unread), which cleanly separates it from formstack_create_submission and formstack_get_submission. An agent can identify the operation without opening the 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?

The description implies usage context (modify an existing submission rather than create one) and points to formstack_list_form_fields for obtaining field IDs, which is a useful cross-reference. However, it never states when to choose this over alternatives or any prerequisites beyond the field-ID lookup.

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