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

Annotations already establish readOnlyHint=false, destructiveHint=false, and idempotentHint=false. The description adds meaningful behavioral context by disclosing that the call marks the count as reconciled (a non-read-only side effect) and by listing the returned data. It does not contradict the annotations.

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 main sentence is a long run-on that packs inputs, outputs, and side effects together; it is readable but not optimally structured. The standalone 'Free.' adds an extra sentence whose relevance to invoking the tool is unclear and does not earn 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?

Despite having no output schema, the description tells the agent what the tool returns (expected balance, difference, vouchers) and what side effect it has. Combined with the complete input schema and annotations, this is sufficient for correct invocation, though it omits error/edge-case behavior such as what happens with no previous count.

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?

All three parameters have schema descriptions (100% coverage), so the baseline is 3. The description restates counted_minor and date in prose but adds no new semantic information about them, and it says nothing about the optional float parameter beyond what the schema already says.

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 states a specific action—counting the tin and reconciling—with required inputs (counted cash in minor units, date) and concrete outputs (expected balance, difference, vouchers since last count). It also names the side effect (marks reconciled), which clearly differentiates it from siblings like float_report and voucher_add.

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 a use case ('give the cash counted... and the date') and the schema notes when to omit the float parameter, but it never tells the agent when to prefer this tool over siblings such as float_report or replenish_request, nor does it state any exclusions or prerequisites.

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