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

Annotations already declare readOnly, idempotent, closed-world, non-destructive, so the safety profile is fully covered. The description adds what data categories are computed (regime derived from S&P 500 trend and VIX) but says nothing about data freshness, update cadence, or source — the traits a market-data tool most needs to disclose. Additions beyond annotations are modest.

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?

Front-loaded with the headline purpose, then the payload inventory, then example queries — good ordering with no filler. The payload enumeration is dense and slightly list-like, but every item is a distinct data category an agent would want to know is available.

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?

An output schema exists, so return values need not be explained, and the description nonetheless signals breadth of coverage. The remaining gap is operational context: no note on how current the data is or whether markets must be open — relevant for a 'backdrop' snapshot.

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?

Zero parameters, so the baseline of 4 applies; there is no parameter semantics to explain and the description correctly spends no words on inputs.

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?

Specific verb+resource ('Current U.S. market backdrop in one call') with the exact contents enumerated: regime taxonomy, VIX level/percentile, Fed funds, 2y/10y yields, curve shape, and FOMC meetings with implied odds. Clearly distinguishes it from siblings like get_daily_brief or get_company_context, which are company- or brief-oriented rather than macro backdrop.

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?

Provides three concrete trigger phrasings ('what's the market backdrop?', 'when is the next Fed meeting?', 'odds of a rate cut?') that make the intended use obvious. It stops short of naming an alternative or stating when NOT to use it, so it is clear context without explicit exclusions.

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