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

Annotations already declare readOnlyHint=false, destructiveHint=false, and openWorldHint=false, so the safety profile is covered. The description adds real behavioral context beyond that: this is a full-field replacement, not a merge, so untouched fields may be overwritten. It does not disclose permissions, reversibility, or what happens to imageStorageKey, which a mutation tool of this shape would benefit from.

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 short sentences, zero waste, with the replacement semantics front-loaded before the operational instruction. Appropriate size for the message it conveys.

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 5-parameter mutation with a nested required object, no output schema, and zero schema description coverage, the definition is far too thin. An agent gets no sense of the identity-scoping parameters, the optional imageStorageKey, or what the call returns.

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 0% across 5 parameters, including a nested 'fields' object with five required sub-keys, so the description carries the full burden and largely fails it. 'Send every field back' hints that fields must be complete, but projectId, siteId, productId, and imageStorageKey are never mentioned or explained.

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 ('Replace a product's fields'), and the word 'Replace' distinguishes it from create_product, delete_product, and set_product_status without needing the schema. It stops short of explicitly naming which sibling it supersedes for partial edits.

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?

'Send every field back' implies full-replacement semantics rather than a partial patch, which is genuinely useful selection guidance. It never names an alternative tool or states when not to use it, so the guidance is implied rather than explicit.

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