get_month_summary

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

With no annotations provided, the description carries the full burden. It discloses the tool's output components and default month behavior. Although it does not explicitly state it is read-only or discuss side effects, the read-only nature is implied by 'Spend summary' and the absence of any warning. This is adequate for a simple lookup tool.

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 two sentences, front-loaded with the tool's identity, followed by output details and a usage hint. Every sentence is informative and 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 simple tool with no output schema and no annotations, the description provides all essential information: purpose, month parameter format and default, output contents, and a usage scenario. It is complete for the tool's complexity.

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?

The input schema only defines 'month' as a string with no description. The description adds crucial semantics: 'YYYY-MM' format and 'default current'. This fully compensates for the 0% schema coverage, making the parameter clear and usable.

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 a clear verb and resource: 'Spend summary for a month' and details the contents (spend total, per-category breakdown, income, transfers, unresolved conflicts). This distinguishes it from sibling tools like get_category_breakdown or query_transactions, which likely focus on narrower aspects.

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 explicitly says 'Call this first for "how am I doing this month"', providing a direct usage scenario. However, it does not mention when not to use it or alternative tools, so it lacks explicit exclusions.

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