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

With no annotations supplied, the description carries the full behavioral burden, and it does disclose several non-obvious traits: the tool is stateful ("register ... once, then poll"), returns a change flag relative to the previous call, costs $0.01 per call in USDC on Base paid via x402 in params._meta, and exposes the HTTP endpoint. What it does not explain is how the watch is scoped or identified across calls (caller key, watch id), which matters for a stateful endpoint.

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 purpose sentence is front-loaded and well-formed, but the price is stated twice ("$0.01/call" and then a full "Price: $0.01 per call in USDC on Base (eip155:8453), paid with x402 in params._meta[...]") and the raw HTTP endpoint adds little for an MCP caller. Two of roughly five sentences are redundant or transport-level filler.

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?

There is no output schema and no annotations, so the description must define the return contract, and "current screen result plus whether it changed" is only a sketch of an unspecified payload. For a paid, stateful polling endpoint the definition should say what identifies the registered watch and what the change flag is keyed against; that gap is real though not fatal for a two-optional-param tool.

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 params are documented in-schema, so the baseline is 3. The description only restates "company name or wallet address" without adding the constraint that neither param is required but presumably at least one must be supplied, which is the one piece of parameter meaning the schema leaves ambiguous.

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 first sentence gives a specific verb and resource: register a company name or wallet address, then poll for changes, returning the current screen result plus a changed-since-last-call flag. That is materially more informative than the bare name `watch`, though it never names the sibling it should be chosen over (e.g. x402check__check, x402check__delta, or x402check__batch).

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?

"Built for recurring compliance monitoring" and "poll for changes" imply the when-to-use case well enough to act on. However, there is no explicit when-not guidance and no named alternative for one-shot lookups (x402check__check) versus diffing (x402check__delta), so the agent must infer the routing decision from the sibling list.

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