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

Annotations already cover readOnly/idempotent/non-destructive/openWorld. The description adds genuinely useful behavioral context beyond that: a per-call price ($0.008 USDC), and that the dataset is masked unless unlocked via x_api_key or payment_signature. What it omits is rate limits, latency, and whether unmasked results differ structurally.

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?

It's a single dense sentence with the price front-loaded in parentheses and the payload enumerated after—efficient and skimmable. The long enumeration of ten market signals is arguably padding, but each name is informative rather than marketing fluff, so it mostly earns its place.

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 read-only, no-output-schema tool with three optional params, the description covers what is returned (the enumerated signals), the cost, and the masking/unlock mechanism. It's sufficient to decide whether to call it. It lacks focus-mode return differentiation and any note on data freshness or update cadence.

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?

Schema description coverage is 100%, so the schema already documents focus, x_api_key, and payment_signature. The description mentions the paid/unmasked gating concept but adds no format or syntax detail beyond the schema (e.g., no guidance on paying without a key). Baseline 3 applies when the schema carries the parameter burden.

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 enumerates concrete data sources (S&P 500, Nasdaq, VIX, DXY, 10Y yield, Gold, WTI, Fear & Greed, BTC dominance, DeFi TVL), which makes the verb+resource unambiguous. It's clear this is a macro/market-data feed. Sibling differentiation is weak, though—nothing explicitly distinguishes it from defi_yields or prediction_markets beyond the enumerated metrics.

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?

There is no when-to-use guidance, no alternates named, and no conditions under which this tool should be preferred over defi_yields, token_alpha, or whale_alpha_radar. The 'focus' enum hints at scoping, but the description never states when to pick tradfi vs crypto vs defi focus.

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