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

With no annotations, the description carries the full burden and does substantial work: it discloses patch semantics ("only the keys given change"), clearing via null, and type-dependent value constraints, plus the photo-id restriction. It still omits permission requirements, validation/error behavior on unknown keys, and whether repeat calls are idempotent.

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 sentences, front-loaded with the action, then the value-encoding rules. Every clause (patching, null, type mapping, photo ids) conveys information the schema does not.

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?

An output schema exists, so return values needn't be explained, and the nested answers object is well covered. Missing is how to obtain a valid form_id (presumably via forms_start) and what happens with unknown field keys.

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% (form_id is undocumented), but the description compensates heavily for answers by explaining key-addressing, per-field-type value encoding, and null-clearing. It does not clarify form_id's requirement of being a started draft form, which is the remaining gap.

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?

"Save answers on a draft form" gives a specific verb (save answers) and resource (draft form), and the word "draft" distinguishes it from forms_submit. However, no sibling is named explicitly, so the agent must infer the routing from context rather than being told.

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?

Usage is implied: only draft forms, partial updates allowed, null clears. There is no explicit "use this instead of forms_submit / forms_start" statement, nor a stated precondition that the form must already have been started.

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