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

Annotations already mark this read-only, idempotent, and non-destructive, and the description adds substantial context beyond them: the result is rule-based rather than a forecast, the attestation proves what was read and when, and a successful call settles $0.020 USDC with no charge on failure. This is exactly the kind of practical behavior an agent needs to know. There is no contradiction with the readOnlyHint since the charge is a billing disclosure, not a mutation of market data.

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 dense but every sentence earns its place: result contents, non-forecast clarification, explicit usage rule, negative routing to the sibling, and cost/failure behavior. It is front-loaded with the core output and then adds usage and cost constraints.

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 a single input parameter, full schema coverage, and an output schema present, the description still provides the essential behavioral and output context: full output contents, when to use, when not to use, and cost. Nothing an agent needs to decide whether to call this tool is missing.

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 coverage is 100% and there is only one parameter, slug, which the schema already describes as a Polymarket market slug obtainable from market/signal. The description reinforces that the tool works 'by slug' and routes users to the sibling for discovery, but it does not add meaningfully beyond the schema.

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 names a specific verb and resource: it returns a rule-based verdict on one Polymarket market by slug. It also enumerates the precise contents (lean, 0-100 confidence, reasons, days to resolution, attestation), and explicitly distinguishes itself from market discovery tools like market/signal by stating it is not a forecast model.

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?

It gives an explicit invocation condition: 'MUST be invoked when an agent needs a defensible, timestamped read of a market.' It also provides an exclusion and alternative: 'Do NOT use to discover markets (use market/signal).' The fee and failure behavior further clarify when calling it is appropriate.

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