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

Annotations already declare readOnly/idempotent/non-destructive, so safety is covered. The description adds genuinely useful behavioral context beyond that: prices may have moved since the scan and an arb can close at any time, which warns the agent the data is stale and volatile. It does not cover pagination or result limits, but the staleness warning is real added value.

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, front-loaded with the definition and ending with the volatility caveat. No filler, though the opening sentence is dense and slightly concept-heavy for a tool description.

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, so return-value structure need not be explained, and annotations plus full schema coverage carry the rest. The missing piece is routing guidance against the `middles` sibling; otherwise an agent has enough to call it correctly.

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 the four parameters are already documented. The phrase 'how a stake would split' loosely reinforces the `stake` parameter, but the description adds no format or constraint detail beyond the schema. 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?

States the resource precisely — spots where opposite-side prices sum to under 100% implied — and even describes the output content (stake split). However, it never gives a verb (list/find) and does not differentiate from the sibling `middles`, which is the closest conceptual neighbor for a betting agent.

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?

No when-to-use, when-not-to-use, or alternative naming appears. A reader must infer that this is the tool for arbitrage questions and cannot tell from the text why they would pick it over `middles`, `game_lines`, or `calc`.

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