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

Annotations already declare this a safe, idempotent, read-only, non-open-world calculation, so the safety profile is covered. The description adds genuinely useful context the annotations do not: the default interest rate source (RBI weighted average lending rate on fresh housing loans) and that it is the latest month and provisional. It still says nothing about how LTV caps vary by loan size or what the returned figures look like.

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?

A single dense sentence with the market ('INDIA.') front-loaded and the scope stated before the default-rate caveat. No wasted clauses, though the all-caps market tag and semicolon-chained outputs make it slightly terse.

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 three-parameter calculator with full schema coverage and annotations carrying the safety profile, the description covers the operation, its outputs, and the default-rate assumption. The absence of an output schema is mitigated because the description enumerates the three returned values; only edge-case behavior for LTV caps is unstated.

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 loan_amount, tenure_years, and interest_rate are already documented, giving a baseline of 3. The description corroborates the optional interest_rate by explaining its fallback source, but adds no units, bounds, or formatting beyond the schema.

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?

The description names the resource (home loan EMI) and enumerates the outputs — EMI, total interest, and RBI loan-to-value caps — for the India market, which no sibling covers. It is a noun phrase rather than an explicit verb like 'calculate', but the intent is unambiguous and distinguishable from the price/tax/guide siblings.

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?

There is no statement of when to use this tool versus alternatives such as taux_courants, acheter_ou_louer, or compare_states_in, nor any prerequisite guidance. The only conditional info is about the default rate, which is a parameter detail rather than usage routing.

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