account_period_summary

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

No annotations are provided, so the description must fully cover behavioral traits. It discloses that the tool is read-only and mentions the report source, but does not describe error handling, permission requirements, response format, or what happens if the account is invalid. The description is insufficient for an agent to understand side effects or limitations.

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 primary purpose, and avoids unnecessary words. It could be slightly more structured by breaking down the outputs explicitly, but it is concise and informative.

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 the lack of an output schema and annotations, the description should explain the return format more completely. It lists the output fields (opening balance, etc.) but does not specify whether the result is a single object or list, data types, or pagination. For a summary tool with 5 parameters, the description provides adequate but not thorough context.

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 has 100% coverage with descriptions for all 5 parameters. The description adds minimal extra meaning beyond the schema (e.g., 'supports department filtering' is already in the schema). According to guidelines, baseline is 3 when coverage is high, and the description does not significantly enhance parameter understanding.

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 clearly states the tool gets a period summary for an account, specifying the exact outputs (opening balance, total debits/credits, closing balance, transaction count), and distinguishes it from sibling tools like 'query_account_transactions' and other summary tools.

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 mentions it uses the General Ledger report and supports department filtering, but provides no explicit guidance on when to use this tool versus alternatives like 'get_balance_sheet' or 'query_account_transactions'. It lacks usage context or when-not-to-use instructions.

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