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

With no annotations, the description carries the full burden and does well: it discloses the price ($0.01 USDC on Base via x402), that no account/API key/invoice is needed, the expected volume (~170/day), and the important caveat that 'new' means new-to-us rather than newly-created. It does not describe the shape or fields of the returned listing, which is the remaining gap.

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?

Front-loaded with the pricing/payment model, followed by scope and the 'new to us' caveat. Every sentence carries information, though the ordering jumps between price, invocation flow, and definition, which is slightly less smooth than it could be.

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?

No output schema and no annotations mean the description must explain the operation, and it covers pricing, invocation, volume, and scope definition adequately for a paid discovery tool. It stops short of describing what a served response contains, which would be the one missing piece for an agent that has to decide whether the $0.01 call is worth it.

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 both `days` and `payment` are already documented in the schema. The description reinforces the payment semantics (omit vs. supply) but adds no syntax or meaning for `days` beyond what the schema states. Baseline 3 is appropriate when the schema does the heavy lifting.

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 states the resource ('new services') and elaborates that these are services that 'appeared recently, roughly 170 a day,' so an agent knows this is a discovery/listing tool for recently-seen services. It distinguishes itself in concept from date-window tools like get_weekly_changes, but it never names an alternative sibling, so the differentiation is implicit rather than explicit.

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 two-step payment flow is spelled out clearly: call without `payment` for the requirements, call again with `payment` to be served. However, there is no guidance on when to prefer this over siblings like search_agents, get_rankings, or cheapest_that_works, and no exclusions. Usage is implied rather than directed.

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