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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false, and closed-world, so the safety profile is fully covered by structured data. The description adds no behavioral context beyond those hints — no notes on edge cases such as apy_pct=0, compounding='none', or how duration interacts with the frequency — so it clears the lower annotated bar without adding much.

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?

Two short sentences, front-loaded with the operation and its inputs. The trailing 'Returns: {initial_amount}' reads as an unfilled template placeholder and is wasted space for a pure-function calculator, but the rest is efficient.

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?

An output schema exists, so return values need not be explained, and the annotations cover the safety profile — the description is therefore not required to carry much. However, the 'Returns: {initial_amount}' placeholder is uninformative and no guidance distinguishes this from the many overlapping crypto/interest calculators, leaving a real selection gap.

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 amount, apy_pct, duration_days, and the compounding enum are all already documented in the schema, putting this at the baseline. The phrase 'optional compounding' is slightly misleading because compounding is a required field in the schema (though its enum includes 'none'), which is a minor tension rather than added clarity.

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 ('Calculate staking rewards') plus the determining inputs (APY, duration, compounding), so the agent knows what computation is performed. It does not differentiate from near-neighbours such as calculate_compound_interest, calculate_impermanent_loss, or calculate_mining_profitability, 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 only routing guidance is 'See list_bundles for related crypto calculators', which points at a discovery tool rather than saying when to pick this over a sibling like calculate_compound_interest. Usage context is implied (staking-specific math) but no when/when-not conditions are given.

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