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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, so the safety profile is covered. The description adds meaningful behavioral context by specifying that the calculation must use the official 1405 tariff and must never be estimated, which informs the agent that exact official values are required rather than approximations. This goes beyond what the schema and annotations state.

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?

The description is three short sentences with no filler. It front-loads the core purpose, immediately gives the critical sibling distinction, and ends with a concise behavioral rule. 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 three-parameter calculation tool with no output schema, the description gives enough context about source (1405 tariff), exactness, and sibling differentiation. It does not explicitly describe the return shape, but for a fee calculator the output is fairly inferable. The rich schema and annotations fill the remaining gaps.

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%, and the schema already provides meaningful descriptions for doc_type, amount_toman, and obligor_count, including rate-based versus fixed-fee distinctions. The description does not add parameter-level semantics, but the baseline of 3 applies because the schema carries the full weight.

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 states a specific verb ('Calculate'), a clear resource (حق‌التحریر, the notary fee), and a specific basis (the official 1405 tariff for دفاتر اسناد رسمی). It explicitly differentiates from حق‌الثبت by naming calculate_stamp_duty, so an agent can distinguish this from its most similar sibling without opening 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?

The description gives an explicit when-not/alternative statement: 'Distinct from حق‌الثبت (use calculate_stamp_duty for that).' It also instructs the agent to 'Never estimate the tariff', which sets a clear execution expectation. This is sufficient routing guidance within the calculator sibling group.

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