MyFinancial Market Data Guide

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

The annotations declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, so the tool is safe. The description adds the behavioral fact that this is a meta-tool (returns a guide), not a data operation, and signals an expectation of high importance ('IMPORTANT'). It does not describe output format or length, but given the no-parameter, no-side-effect nature, the description provides adequate context.

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 a single sentence but dense; it front-loads the critical directive ('Call this FIRST') and packs in the key contents. It is efficient with no fluff. It could be slightly more structured (e.g., bullet points) but for a short description it is appropriately 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?

For a no-parameter, read-only tool, the description covers the essential context: what the tool does, why it matters, and what it contains. It doesn't specify return format or length, but as a guide, those details are likely evident from the content. Given the rich sibling list and the tool's meta-role, the description sufficiently prepares an agent to call it first and understand its purpose.

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 0 parameters, so there is no schema to explain. The description correctly focuses on what the tool returns rather than any input semantics. With parameter count 0, the baseline for this dimension is 4, and the description does not introduce any confusion. It clearly sets expectations for output content.

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 clearly states that the tool returns a complete guide organizing all tools by category, with critical rules and usage patterns. It identifies the resource ('complete guide') and the action ('returns'), and its purpose as an orientation/onboarding tool. It does not explicitly name a sibling to differentiate from, but its role as an index is distinct enough from the data-retrieval siblings.

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 instructs 'Call this FIRST', which is strong when-to-use guidance. It also lists what the guide includes (rules, patterns, cross-tool suggestions), which implies it should be consulted before using other tools. It doesn't mention when not to use it, but the 'FIRST' directive is clear and compelling.

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