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

Annotations already declare readOnly/openWorld/non-destructive, so the safety bar is low, yet the description still adds real behavior: comparison is strictly at the same line, Kalshi's fee is baked into the price, and no model output is produced. It does not say what happens on ambiguous inputs (e.g., both `game` and `team` supplied) or how results are ordered/truncated.

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: usage examples come first, then the scope/limitation statement. The eight-book enumeration is long but earns its space by defining coverage.

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 must hint at returns, and it does ('cheapest venue per side, Kalshi fee included'). For a four-optional-parameter read tool with full schema coverage and annotations, this is nearly complete; the remaining gap is behavior when no parameters are supplied.

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 baseline is 3. The description reinforces the market dimension by naming moneyline/spread/total and clarifies that fees are included in the prices returned, but it adds nothing on how `game` and `team` relate (alternatives? both required?) or how `limit` interacts with the default board.

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?

Names a specific resource (NBA moneyline/spread/total board) and a specific operation (Kalshi prices set beside eight named sportsbooks), plus a distinguishing scope: 'cheapest venue per side, Kalshi fee included. Market prices only, no model.' An agent can tell this apart from nba_prop_board (props) and calculate_ev (modeling) without opening a 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?

Opens with two concrete 'Use for' example queries that pin the intended scenarios (line comparison, cheapest price). It gives a clear context of use but no exclusions or explicit routing to siblings when the question shifts to props, EV, or injuries; the agent must infer that boundary.

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