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

With destructiveHint=true and idempotentHint=false already declared, the description earns credit by disclosing the actual effect — 'the seller no longer sees it' — which is the concrete consequence of the destructive flag. It does not address reversibility (whether contact can be re-shared later) or what happens on a repeat call, which the non-idempotent hint makes relevant.

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, no filler, and the actor plus effect are front-loaded before any nuance. 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 one-parameter mutation with no output schema and annotations covering safety, the description supplies the essential effect and precondition. It could go further on reversibility and repeat-call behavior given idempotentHint=false, but nothing critical for correct invocation is missing.

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% and the single order_id parameter is fully documented in the schema with format example ('or_…'). The description adds no parameter-level meaning beyond what the schema already supplies, so the baseline of 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 ('take back') and resource ('the contact you shared'), names the actor (Buyer) and ties it to the originating action ('on buy (share_contact)'). It is distinguishable from siblings, though 'share_contact' is not itself a sibling tool, which leaves the reference slightly ambiguous.

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 clear usage context: the caller must be the buyer and must have previously shared contact via buy. It does not state when-not to use it or what alternative exists (e.g. re-sharing contact), so it stops short of the 5 bar.

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