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

No annotations are provided, so the description carries the full burden. It discloses the cost ('Costs 2 credits per call') and enumerates the exact outputs (top/worst sectors, advance/decline ratio, momentum scores, sector technical analysis). This goes beyond a simple action statement and gives the agent a concrete picture of what the tool returns, though it omits details like data freshness or interpretation guidance.

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 well-structured: purpose sentence, usage sentence, returns list, coverage list, and cost. It is front-loaded with the core purpose and each sentence adds value. It is slightly longer than minimal, but every part is relevant, so it earns a 4 rather than a 5 for being concise.

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 the tool has no parameters and no output schema, the description adequately explains what it returns and what sectors it covers. It also mentions the credit cost. It does not describe how to interpret the momentum scores or the exact format of results, but for a no-parameter analysis tool, this is reasonably complete. A 4 is fair.

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?

The tool has zero parameters, so the schema is empty (coverage 100%). Per the rubric, a 0-parameter tool receives a baseline of 4. The description adds no parameter details because none exist, and no further compensation is needed.

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 ('Analyze') and resource ('sector rotation and market breadth'), and clearly defines the tool's function: identifying gaining/losing momentum sectors. It distinguishes itself from siblings like get_market_regime or get_risk_index by focusing on sector-level analysis, making its purpose unambiguous.

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 explicitly says 'Use this tool to identify which sectors are gaining or losing momentum, helping with sector allocation and rotation strategies.' This provides a clear when-to-use context. It does not explicitly mention when not to use it or name alternatives, but the use case is well-defined, so a 4 is appropriate.

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