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

Annotations already carry readOnlyHint/destructiveHint/openWorldHint, so safety is covered. The description adds real domain semantics beyond that: a session with no closeTime is still open, and it enumerates what each record contains (opener, closer, opening float, declared closing amounts). Pagination and row limits are not addressed, which keeps it from a 5.

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?

Front-loaded with what it is, then use cases, then return contents, then the routing note to the sibling. Every sentence carries distinct information with no filler.

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?

No output schema exists, and the description compensates by stating what comes back (who opened/closed, opening float, declared closing amounts). Combined with the open-session rule and the sibling hand-off, an agent has everything needed to call it correctly.

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%: startDate, endDate, outlets, and stations are all documented in the schema, including ISO 8601 format and the inclusive-bare-date rule. The description adds no parameter-level detail beyond reinforcing the date-range window, so the baseline 3 applies.

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 resource and scope: register sessions (shifts) opened and closed in a date range, tied to a concrete UI location (Reports → End of Session). It also disambiguates from the closest sibling by naming get_session_report as the single-shift money report.

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 concrete triggering questions ('what shifts ran yesterday', 'who closed the register last night', 'is a session still open'). Explicitly names the condition that routes to the alternative: pass an id to get_session_report for one shift's full money report.

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