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

Annotations already declare readOnlyHint=true, destructiveHint=false, and openWorldHint=false, so the safety profile is covered. The description adds value beyond that by naming the return payload (finalCapital, totalEarned, apy, growthTable), which matters since no output schema exists. It does not mention rounding, interval assumptions, or error behavior, so it is short of excellent.

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 short sentences, zero waste, front-loaded with the operation and followed by usage triggers and return keys. Every sentence 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 projection tool with no output schema and a fully documented 5-param schema, the description covers purpose, triggers, and the four return keys, which is what an agent needs to invoke it correctly. Minor gaps remain around assumptions (e.g. that funding rate is held constant across intervals), preventing a 5.

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 all five parameters are already documented in the schema, including the 8/1 interval enum and the reinvestPct default. The description only echoes units through its example ('0.01% funding for 90 days'), adding no real semantics beyond the schema. Baseline 3 applies when the schema carries the load.

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 ('Project capital growth from reinvesting perpetual futures funding income (compounding carry)'), which cleanly separates it from nearby siblings like run_carry_trade, run_funding_cost, and run_funding_arbitrage. An agent can identify the operation 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 two concrete trigger utterances ('how much will I make compounding 0.01% funding for 90 days?' and 'what's my APY on this carry position?') that map directly to the intended use case, which is strong context. It stops short of naming when-not-to-use or pointing at an alternative sibling such as run_funding_breakeven, so it is not a full 5.

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