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

With no annotations, the description carries the full burden. It discloses the core behavior (per-step recomputation of EMI and total interest) and supplies a concrete input example, but says nothing about what happens when 'deltas' is omitted, whether a default step grid applies, or the shape of the returned comparison.

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 sentences, front-loaded with the computation and followed by a compact literal example. Every element earns its place; only the example's redundancy with the schema keeps it off a 5.

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?

There is no output schema, and the description only broadly names the return values without indicating structure (per-delta rows, units, sign convention). For a 5-parameter analysis tool it is adequate but leaves the response shape ambiguous.

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%, including ranges and the 'give months or years' hint, so the schema does the heavy lifting. The description's example pins three of the five fields but adds no meaning for 'deltas', the parameter most likely to be misused.

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 computation: takes principal, annual rate and tenure, and returns how EMI and total interest shift as the rate moves in small steps. That distinguishes it in substance from the plain 'emi' sibling, though no sibling is named explicitly.

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 when-to-use is only implied by the word 'sensitivity' and the worked example; there is no statement of when to prefer this over 'emi' or of any preconditions. An agent can infer the scenario but must do the inference itself.

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