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

Annotations (readOnlyHint=false, openWorldHint=false) only establish that this is a bounded mutation; the description adds genuinely new behavior — a 6-hour acceptance window with automatic cancellation and no penalty — which an agent cannot infer from structured fields. It omits whether stake is escrowed or what happens to state after cancellation, keeping it below 5.

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 with zero filler; the most decision-relevant constraint (the 6-hour auto-cancel) is front-loaded right after the action statement.

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 six-parameter mutation with no output schema, the description covers the lifecycle trigger but says nothing about what is returned (e.g., a deal identifier likely needed for later deal_status or accept_deal calls). That is a meaningful gap for a create operation.

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 100%, so agent_id, secret, partner, stake, domain and outcomes are all documented in the schema already. The description adds nothing about the meaning of the outcomes list ordering or the domain values, hitting the baseline.

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?

"Open a deal between your bot and another" is a specific verb plus resource and makes the actor roles clear, which implicitly separates it from accept_deal (the counterpart's action) and deal_status. It never names those siblings explicitly, so it sits just short of a 5.

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?

The description implies the create-then-accept flow by saying the other bot must accept, but it never states when to choose open_deal over alternatives such as report_outcome or check_trust, nor does it give prerequisites beyond the schema's 'from register' hints.

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