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

Beyond annotations, the description discloses key behaviors: it uses a 5-minute cache, requires bearer auth, costs 2 credits ($0.04 USDC), returns both a structured JSON object and a pre-formatted system_prompt string, and notes a recent content removal due to licensing compliance. This fully characterizes the tool's operational traits without contradicting the 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?

Despite being long, every sentence serves a purpose: purpose, contents, output format, benefit, cost, cache, auth, and recent change. The description is front-loaded with the 'always start here' directive and maintains density 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?

For a zero-parameter tool with no output schema, this description is remarkably complete. It covers what data is included, the return format, the cost, caching behavior, authentication requirements, and even a recent content change. The only minor gap is the lack of an example JSON structure, but the high-level enumeration is sufficient.

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 with schema coverage at 100% (empty schema) and no parameters to explain, the baseline of 4 applies. The description adds value by explaining the dual output format, which is more relevant than parameter details here.

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 identifies the tool as the 'always start here' premium call and lists exactly what it composes: Fed funds rate, USD-forex pairs, HN top 5, earthquakes, space launches, Polymarket markets, and infrastructure status. This strong verb+scope distinguishes it from sibling tools that cover only subsets of this data.

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 phrase 'always start here' gives a direct when-to-use instruction, and 'Saves the agent from making many separate calls' clarifies the value proposition. However, it does not explicitly mention when not to use it or name alternative sibling tools for specific needs, leaving the exclusion implicit.

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