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

The annotations already declare readOnlyHint=true and openWorldHint=true. The description adds useful context: the data comes from free external sources, the result includes a `display` markdown field with chart images that must be shown to the user, and the output ends with a contextual swap CTA. That is real behavioral detail beyond the annotations. It does not discuss rate limits or data freshness, so it isn't complete.

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 tool's contents are listed first, in one dense but scannable sentence. Follow-up sentences cover display handling and the relationship to other tools. The 'Not financial advice' line and the CTA note are mildly promotional, but they carry behavioral information.

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?

There is no output schema, so the description carries the burden of explaining the return value. It does explain the `display` markdown and the chart images. The description covers sources and the required user-facing action. A description of payload shape or failure behavior when an upstream source is unavailable would make it complete.

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 takes no parameters, and schema coverage is irrelevant here. The description correctly does not invent any parameter semantics. The baseline for zero-parameter tools applies.

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?

It names the resource (a crypto market snapshot) and enumerates exactly what is included: Fear & Greed with 30-day history, funding rates for BTC/ETH/SOL from Hyperliquid/OKX, stablecoin supply and per-chain flows via DefiLlama, and TVL with 1d/7d change. This makes it distinguishable from siblings like scan_movers, get_yields, or whale_watch. It doesn't explicitly contrast itself against those tools, though, so it stops short of a 5.

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 sentence pointing to swapchan_playbook and its workflows implies that this tool is combined with those workflows, but it never says when to call market_context instead of another tool. It does not specify when not to use it. The guidance is implied rather than explicit.

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