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

Annotations already establish that this is a safe read (readOnlyHint=true, destructiveHint=false, openWorldHint=true). The description adds value beyond them by disclosing the return contract and, notably, the structured error envelope with a 'retryable' flag, which tells the agent how to react to failure. It stops short of describing pagination or result ordering.

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 one-line purpose is front-loaded, followed by a tight parameter list and a return note. It is close to minimal for the information conveyed, though the docstring-style 'Args:'/'Returns' formatting is slightly verbose.

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 an output schema present, the description needn't detail return values, yet it still adds the error-envelope contract as a useful bonus, and all four parameters are documented. The one real gap is usage context – when to prefer this over sibling scanners.

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 0%, so the description carries the full burden and does so well: it names example exchanges, enumerates the valid timeframes, maps the -3..+3 rating scale to semantic labels, and states the max row limit of 50. This adds substantial meaning beyond the bare typed 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 states a specific verb and resource: 'Filter coins by Bollinger Band rating,' which is clear and actionable. It does not, however, differentiate itself from the nearby sibling 'bollinger_scan', leaving some ambiguity about which of the two to pick.

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 is essentially a parameter list with no when-to-use guidance, no prerequisites, and no mention of alternatives. A reader cannot tell from this text why they would choose rating_filter over bollinger_scan or another scanner.

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