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

No annotations provided, so the description carries the full burden. It discloses what is modeled (nil-rate band, residence nil-rate band, etc.) and what is excluded (lifetime-gift history). This is comprehensive for a calculation tool with no side effects. It could mention if results are cached or if it makes external calls, but that is likely unnecessary.

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: first defines purpose and rules, second clarifies limitations. No wasted words. Information is front-loaded with the core purpose.

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?

Given 15 parameters and no output schema, the description adequately covers the modeling scope and exclusions. It does not describe the return format (e.g., breakdown by bands), which would be helpful, but the main purpose and constraints are clear.

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 baseline is 3. The description adds value by explaining the overall modeling context (e.g., '£2m taper', '36% at 10%+'), which helps the agent understand how parameters interact beyond their individual descriptions.

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 specifies exactly what the tool does: estimate UK Inheritance Tax bill for 2025/26 with detailed rules listed. It distinguishes from sibling tools (e.g., check_rnrb, gift_7_year_timeline) by focusing on full IHT estimation rather than a specific aspect.

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 states 'Illustrative only — excludes lifetime-gift history,' setting clear expectation of scope and limitation. While it doesn't explicitly compare to sibling tools, the purpose is distinct enough that an agent can infer when to use it (IHT estimation) vs. other tools (gift timeline, care costs).

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