Purchase a market delta

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

With no annotations, the description carries the full burden. It discloses that the tool involves a purchase (cost of 0.05 USDC) and is read-only. However, it does not elaborate on side effects (e.g., if purchase is refundable, rate limits, or whether multiple calls incur multiple charges).

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 a single concise sentence that front-loads the key action and resource. No unnecessary words.

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?

Given no output schema and no annotations, the description explains the action and required inputs adequately but omits important context such as the format of the returned report, any limits on usage, and whether the cost is deducted from a balance. More detail would improve completeness.

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%, so baseline is 3. The description does not add meaning beyond what the schema already provides for both parameters ('slug' and 'since'). The schema descriptions are already clear.

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 clearly states it purchases a read-only probability-change report for a market, specifying the cost (0.05 USDC) and the time filter (since an ISO 8601 UTC timestamp). This distinguishes it from siblings like get_market_brief (brief info) and get_market_pricing (pricing).

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 implies usage when a probability-change report since a timestamp is needed, but does not explicitly state when to use this tool versus alternatives or provide exclusions. No guidance on scenarios where this tool should not be used.

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