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

Annotations already cover read-only, idempotent, and non-destructive, but the description goes well beyond them by stating this is an unsigned transaction the caller must send, the exact proof logic that determines the settlement price, the two-day no-print edge case, the 14-day void(id) fallback, and the output (settlement price and per-share payoff). That is substantive behavioral context an agent could not get from structured fields.

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?

The purpose is front-loaded, but the body is two sprawling run-on sentences with nested parentheticals that are hard to parse on a first read. Most content earns its place, but the packaging slows comprehension of what should be a short settlement rule set.

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?

With no output schema, the description correctly compensates by stating what the call produces (settlement price and what it pays a share) and what the alternative build is (void(id)). Combined with full schema coverage and annotations, an agent has enough to call it correctly; only the absence of sibling routing keeps it from a 5.

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 every parameter already carries its own documentation, including the acceptable series_id vs. symbol/expiry/strike/type alternative. The description adds conceptual framing (expiry time, rounds) but no additional syntax or format guidance, so the baseline 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?

The opening names a specific resource (a series) and its settlement condition (after Friday 8pm New York expiry, last round at or before it) and explicitly frames the output as an unsigned transaction. The purpose is unmistakable, but it never contrasts itself with near-siblings such as settle_cover or claim_option, so an agent must still infer which settlement tool applies.

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 spells out the triggering conditions in detail: expiry passed, proof holds (next round printed after expiry or it is the feed's latest), the no-print-in-two-days branch, and the 14-day void(id) fallback. It also notes 'Anyone may send either,' clarifying permissions. What is missing is any explicit routing against alternative tools, so it stops short of a 5.

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