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

No annotations are supplied, so the description carries the full burden, and it does disclose two behaviors an agent genuinely needs: no credentials are required and the call costs no CRD. It also frames the tool as informational by describing exactly what metadata comes back. Minor gaps remain around rate limits, caching, and the shape of the returned price list.

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?

Two sentences, front-loaded with the purpose, followed by the optional parameter's effect and the auth/cost guarantees. No redundant restatement of the tool name and nothing wasted.

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 single-optional-parameter read tool with no output schema, the description covers purpose, parameter effect, auth requirements, and cost, and it enumerates the returned fields (scheme, network, asset, prices). It stops short of describing the structure of the per-project price list, which is the one thing left for the agent to discover at call time.

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 the baseline is 3, but the description adds real meaning beyond the schema: passing project_id switches the response from generic scheme/network data to that project's credit price list. That is an effect statement the bare schema text ('Project whose credits you want priced') does not convey.

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 gives a specific verb and resource ('Discover how to pay Cred with x402') and enumerates what is returned: accepted scheme, network, asset, and prices. That clearly separates it from the transactional sibling buy_credits_x402, though it never names that sibling explicitly, so an agent must infer the pairing.

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?

Usage is implied rather than stated: this is the pre-flight discovery step before buying credits via x402, and the project_id note tells the agent how to get project-scoped pricing. There is no explicit 'use this before X, use Y to actually purchase' routing, and no stated exclusions, so it lands at implied-usage rather than true guidance.

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