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

Annotations declare readOnlyHint=true and destructiveHint=false, and the description adds substantial context beyond them: the reference exchange set, exact threshold bands (0.25%/1%), the meaning of the 'insufficient' status, and the exclusion of inverse, dated and unlisted contracts. This is exactly the kind of behavioral detail annotations cannot carry.

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?

Long but dense and front-loaded: the core check is stated first, then the exchange set, then thresholds, then usage, then the return shape. Every sentence carries information, though the return-field enumeration is slightly list-heavy for a description.

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 returned fields (status, summary, median, peerMedian, spreadPct, deviationPct, sources, quotes, thresholds_pct, as_of) and defines the status vocabulary, so an agent knows both inputs and outputs well enough to call and interpret it.

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 real meaning by stressing that the symbol must be the exchange-native perp symbol (with per-exchange examples such as BTCUSDT on bybit and ETH-USDT-SWAP on okx) and by explaining that the chosen exchange is compared against the rest. That prevents a common cross-exchange symbol mismatch.

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 ('cross-exchange agreement check for one perpetual futures price') and immediately bounds the scope to 7 named exchanges with the chosen one compared against the rest. An agent can distinguish this from sibling workflows like run_cross_venue_arbitrage or run_pre_trade_check without opening any 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?

Gives an explicit trigger ('Use before acting on a live price') plus a worked example question ('is this Bybit BTC price in line with the market?'). It also clarifies when NOT to treat the result as a verdict (insufficient status, non-comparable contract types), which is strong routing guidance.

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