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

Annotations already declare readOnlyHint=true, and the description adds substantial behavioral context: it costs 10 units (most expensive), reads both catalogues, returns formatted text, and warns against repetitive calls. This goes well beyond the annotation and fully discloses operational characteristics.

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 front-loaded with the core purpose ('ONE SNAPSHOT OF BOTH MARKETS') and each subsequent sentence serves a distinct function: scope, usage, alternatives, cost, and loop warning. Every sentence earns its place without redundancy.

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's simplicity (no params, no output schema), the description covers everything needed to call it correctly: what it does, when to use it, cost, alternatives, and output format. Nothing essential is missing.

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, and the description explicitly states 'no arguments,' which is the only clarification needed. With 100% schema coverage (empty schema), the description adds the key fact that no input is required, which is helpful for agents.

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 the exact scope: 'ONE SNAPSHOT OF BOTH MARKETS' combining crypto and US stocks, ranked by Martingale Score with Startingale readings. It explicitly names sibling tools (crypto_overview, stock_overview, search_instruments) and explains how they differ, making it impossible to confuse with alternatives.

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?

It provides explicit when-to-use ('open a conversation' or answer 'how do things look right now') and when-not-to-use guidance, including alternatives for single asset classes and filtered searches, plus a warning against calling in a loop due to cost. This is comprehensive and actionable.

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