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

Annotations already declare readOnlyHint=true and openWorldHint=false, so the safety profile is covered. The description adds genuinely non-obvious behavior: results are dynamic — founding and yearly plans appear only 'while /pricing has them on sale, checked when you call the tool' — and it deliberately withholds the price values themselves. It stops short of describing response structure or pagination, hence not a 5.

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?

Three sentences, front-loaded with what the tool returns, then the volatility caveat, then the invocation trigger. Every sentence carries information the agent cannot get from annotations or schema; nothing is redundant.

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 read tool with no output schema, the description covers scope, freshness semantics, and when to call. The one gap is that it doesn't hint at the shape of the pricing response (e.g., per-plan fields, currency display), which an agent might want since no output schema exists.

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 zero parameters, so the baseline is 4 and there is nothing for the description to disambiguate. It correctly does not waste space restating parameter information.

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?

States a specific verb+resource ('What Liquid State costs today') and enumerates the exact content covered: free read-only API/MCP server, The Feed, The Reserve, x402 per-call USDC terms, plus founding/yearly plans when on sale. This clearly distinguishes it from the sibling tools (get_briefs, get_market_overview), none of which deal with pricing.

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?

Gives an explicit trigger: 'Use when the user or agent asks about price, plans, or how to pay.' That is a clear context for invocation. It does not name an exclusion or alternative, but no plausible sibling competes for this intent, so the guidance is nearly complete.

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