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

Annotations already flag destructive/non-idempotent, but the description adds real substance beyond them: the change propagates to every marketplace in the project and affects what customers can buy, it cannot be undone through the API, and the call is never retried. The timeout-recovery instruction is behavior an agent cannot infer from 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?

Front-loads the core operation and the non-delta constraint in the first two sentences. Slight redundancy: marketplace propagation is stated twice ("passes the new stock to every marketplace" then "Channable passes this change on to the marketplace") and the raw endpoint path adds little for an agent.

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 destructive, non-idempotent batch mutation with no output schema, the description covers everything needed: batch size, value semantics, blast radius, irreversibility, no-retry guarantee, and post-timeout verification. No material gap remains.

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%, so the baseline is 3. The description restates what the schema already documents — offer id semantics and "whole new stock value (not a delta)" — adding emphasis but no new syntax or constraints beyond the nested schema.

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 ("Set the stock of up to 50 offers") and immediately scopes it to the offer-id + whole-value model, which distinguishes it from read-side siblings like channable_list_stock_updates. The agent knows exactly what the call does 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?

Clear operating context: batch limits (up to 50), whole value vs delta, and explicit recovery guidance on timeout ("check the order in Channable before trying again"). It never names a sibling alternative (e.g., using channable_list_stock_updates to verify), so it stops short of full routing guidance.

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