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

Annotations already convey destructive/write behavior, so the description adds valuable specifics: set or replace, removal via limit 0, one currency per period. It does not go into failure modes or auth, but the main behavioral traits are transparent.

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?

Three short sentences, key behavior first, no filler. The budget_status pointer is purposeful.

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?

The core semantics for correct invocation are present, and an output schema exists. It could have stated the monthly default explicitly, but the schema already supplies that, so nothing critical is missing for this simple tool.

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 descriptions cover limit and period; description adds the one-currency rule and reinforces removal via zero. However, category_id and currency remain minimally explained in both description and schema, so the description only partially compensates for the 50% schema coverage.

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 ('Set') and resource ('spending limit for a category'), clarifies replace semantics, and distinguishes from budget_status by naming it as the progress reporter. The scope is immediately recognizable among siblings like set_category_rule.

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?

Gives clear context: use it to set or replace a category budget, pass 0 to remove, and consult budget_status for progress. It lacks explicit when-not-to-use conditions compared with other mutation tools, but the context is sufficient.

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