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

Annotations already establish read-only, non-destructive, open-world behavior. The description goes further by disclosing the fixed-supply assumption and the failure mode (comparable=false plus error when either market cap can't be resolved), which is genuinely useful operational context. It does not cover rate limits or latency, keeping it short of 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?

Front-loaded with the core action, then scope, then caveats, then return shape. Sentences are dense but each carries information; the parentheticals and quoted example slightly lengthen it without waste.

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?

Despite no output schema, the description enumerates the return fields (multiplier, projectedValueUsd, projectedPriceUsd, profitUsd, comparable) and the error condition. Combined with full parameter coverage, an agent has everything needed to call and interpret this tool.

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 coverage is 100%, so the baseline is 3, but the description adds meaning beyond it: chains may be Solana or one of 5 EVM chains and the two tokens can reside on different chains, which explains why tokenChain and compareToChain exist as separate parameters. That cross-chain nuance is not obvious from the schema alone.

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 and resource ('compares two tokens' live market caps ... projects what an investment would be worth'), plus the cross-chain scope. No sibling in the list performs market-cap comparison, and the description makes the capability unmistakable even without reading the schema.

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 an explicit trigger phrase ('Use when user asks "what if this token reaches [other token]'s market cap?"') and bounds the tool's applicability by declaring it narrative-agnostic and pair-agnostic. It also clarifies the model's assumption ('snapshot ratio, not a forecast'), which tells the agent when the output is and isn't appropriate.

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