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

While annotations already set readOnlyHint=true and idempotentHint=true, the description adds crucial behavioral context: the rationale for retirement (no licensed source), the exact return structure, and the semantic meaning of the absent field. It also clarifies that it 'remains callable so existing integrations do not break' – a key behavioral trait not covered by annotations. No contradiction with annotations.

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 longer than average but every sentence contributes value: the 'RETIRED' headline, the reason, the return contract, the zero-flow warning, and the alternative routing. It front-loads the critical information and avoids filler. The structure is coherent and scannable.

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 retired tool with no arguments and no output schema, this description is fully complete. It explains why it exists, what it returns (including field names), how to interpret the result, and where to go for live data. An agent has everything needed to decide not to call it or to handle its response correctly. No gaps.

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 takes zero parameters, and the schema coverage is 100% (empty object). Per the rubric, a zero-parameter tool gets a baseline of 4. The description adds no parameter semantics because there are none to describe; it only confirms 'takes no arguments'. This is sufficient.

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 explicitly states this tool is retired and serves no flow figures, making its purpose unambiguous: it exists to return an explicit absence. It distinguishes itself from siblings by naming live signal alternatives (scan_signals, get_sovereign_reserves, etc.). The verb 'returns' plus the exact response shape leaves no ambiguity about what calling it produces.

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 gives explicit when-not-to-use guidance ('no longer advertised', 'serves no flow figures') and directly names six alternative tools for live signals. It also warns against misinterpreting the absence as zero, which is a critical usage constraint. This is exemplary routing and safety guidance.

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