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

The annotations already declare readOnlyHint, idempotentHint, and destructiveHint=false, so the safety profile is covered. The description adds some behavioral context by saying the budget is the "exact saved" value and that there is "No conversion or payment," but it does not explain missing-budget behavior, permissions, or other read-specific semantics.

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 short, front-loaded with the core operation, then gives the main alternative and a behavioral exclusion. Every sentence contributes useful routing or semantic information.

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 simple read-only, idempotent lookup with rich annotations, the description is sufficient to call the tool and understand its scope. The lack of an output schema means it could say more about the returned budget shape or not-found behavior, but the core contract is covered.

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 0%, so the description must carry parameter meaning. It identifies both inputs and adds useful detail that currency must be an explicit ISO currency, but category remains mostly unelaborated beyond "one category," and no format examples or constraints are given.

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 gives a specific verb and resource ("Read the exact saved budget") and narrows scope to one category plus an explicit ISO currency. It also names list_budgets as the all-categories alternative, so an agent can distinguish the tools without opening schemas.

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?

It clearly implies use when the agent needs a single saved budget for a known category/currency, and explicitly points to list_budgets when all categories are needed. It does not contrast with nearby siblings such as get_budget_actuals or set_budget, so it stops short of full when/when-not guidance.

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