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

Annotations already declare readOnlyHint=false, destructiveHint=false, and openWorldHint=false, so the write/closed-world profile is covered. The description's only added content is the categoryId-optional behavior, which is already stated verbatim in the schema; it says nothing about duplicate budgets, validation failures, or what happens on conflict.

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 front-loaded sentence that states the action and the two modes with no filler or redundancy.

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 7-parameter mutation with no output schema, the description covers the main branch (overall vs. category) but omits how to handle an existing budget, what is returned (e.g., the new budget id), and any side effects. Adequate given the rich schema and safety annotations, but not thorough.

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 86%, so the schema already documents amount, currency, period defaults, date formats, alertThreshold, and the categoryId omission rule. The description merely restates the categoryId distinction, adding no format or syntax detail beyond the structured fields.

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 ('Create') and resource ('personal budget') and names the two creation modes (overall vs. single category), which separates it from create_goal and create_group_transaction. It stops short of explicitly naming sibling tools, so it lands just below 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?

There is no when-to-use guidance, no mention of prerequisites, and no routing to alternatives such as update_budget when a budget already exists or list_budgets to check first. The 'either overall or for a single category' clause hints at a variant, not at when this tool is the right choice.

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