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

Annotations already declare readOnlyHint=true and destructiveHint=false, so the description's job is reduced. The description adds value by mentioning 'direct deposit income' as a distinct component, which is behavioral context beyond the schema. It does not repeat the read-only status, which is fine. Given annotations cover safety traits, the added detail about income types justifies a 4.

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?

Two sentences: first states the content, second provides a sample question. No filler, no repetition of the name, and it's front-loaded with the core content. Each sentence 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?

The tool is relatively simple with one optional parameter and an output schema, so the description doesn't need to explain return values. It covers the main deliverable (total revenue, breakdowns, direct deposit) and the intent. Could mention that it aggregates data, but that's implied. Given the output schema exists, this is sufficient.

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 100%, so the single parameter 'year' is already described ('Calendar year. Omit to use the current fiscal year.'). The description adds the context that the default is the current fiscal year, which is the same as in the schema, so minimal added value. However, it does clarify the year is used for revenue summaries, which is a slight addition. Given high coverage, baseline is 3, so 4 is above baseline because the description enriches the context ('this year' in the sample question ties to the year parameter).

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 it provides total revenue with month-by-month and by-client breakdowns and direct deposit income. It includes a sample question it answers ('how much have I made this year and who are my top clients?'), which makes the purpose explicit. It distinguishes itself from siblings like get_cash_summary, get_client_summary, and get_1099_summary by specifying the revenue focus and breakdown dimensions.

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 implies when to use this tool: for revenue totals and breakdowns, particularly by month and client, and to answer questions about yearly earnings. It does not explicitly name alternatives or state when not to use it, but the sample question provides clear context. Lacks explicit exclusions like 'use get_client_summary for client-specific metrics'.

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