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

The readOnlyHint annotation already establishes that this is a safe, non-mutating calculation. The description adds useful output behavior—'% edge and a BUY / SELL / SKIP signal with a plain-English read'—but does not disclose internal assumptions or edge thresholds. This is adequate but not rich.

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 description is three sentences: function and outputs, use cases, and provenance/track-record context. It is front-loaded and every sentence earns its place, though the final track-record sentence is slightly promotional.

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 simple two-parameter read-only calculator, the definition is complete enough: it names the domain, inputs, outputs, and intended use cases. There is no output schema, but the description gives a reasonable picture of the return value. A bit more detail about how the BUY/SELL/SKIP thresholds are derived would be helpful but not necessary for correct invocation.

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%, and both marketPrice and yourProbability already have detailed descriptions including accepted formats (percentages, decimals, American odds). The description adds no parameter semantics beyond what the schema already provides, 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?

The description opens with a specific verb and resource: 'Calculate the expected-value edge on a Kalshi or Polymarket prediction-market contract.' It names the inputs and the exact outputs (% edge and BUY/SELL/SKIP signal), making the function unambiguous and clearly distinct from siblings like convert_probability or kelly_size.

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 explicitly states when to use the tool: 'Use for "is this contract mispriced", "what is my edge", "should I take this position".' This gives clear context, though it does not name sibling tools or specify when not to use it.

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