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

Annotations already declare destructiveHint=true, idempotentHint=false and openWorldHint=true; the description adds the confirmation requirement and notes the channel header is resolved internally, which is beyond the structured data. It still omits the most consequential mutation detail: whether omitted optional fields are left untouched or cleared, and what a partial failure looks like.

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 with the purpose front-loaded, the safety gate second, and infrastructure notes last. No filler, though the trailing header/auth sentence could be tightened given channelOAuthId is already documented in the schema.

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 and annotations carry the safety profile, so those burdens are lifted. But for a 23-parameter destructive mutation with no idempotency, the description never explains partial-update semantics, identifier precedence (productId vs variationProductId), or which fields are actually editable — the gaps an agent is most likely to hit.

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 100% with all 23 parameters individually described, so the description needn't restate them. It adds a small amount of routing context — that this targets one exact variation and that channel identity comes from the HGRApi header — though the phrase 'ChannelOAuthId resolved internally' sits awkwardly against channelOAuthId being a required input, which slightly muddies rather than clarifies.

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?

A specific verb plus resource ('Changes editable fields of one exact listing variation') and the underlying API call (SaveProductChanges). 'One exact listing variation' implicitly separates it from bulk siblings like hgr_post_searchproduct_savemultipleproductchanges, but no sibling is named explicitly.

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 a real precondition ('Call only after the listing is exact and the user explicitly confirmed the action'), which is useful gating guidance. However, it names no alternatives — nothing tells the agent whether to use this versus hgr_post_searchproduct_savemultipleproductchanges for bulk edits, hgr_update_pricing_rule for rule-level changes, or hgr_post_listingcreate_editpending for pending listings.

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