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

Annotations already flag destructiveHint=true and idempotentHint=false, but the description adds material context the agent cannot get elsewhere: the void is non-destructive to the audit trail ('stays on the record as voided'), a reason is mandatory, and the period must be open. That soft-void semantics is the key behavioral fact an agent needs before invoking.

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 the core action and effect, no filler sentences. The choppy fragments ('Only while its period is open.') read as notes rather than prose but cost nothing in length and keep the constraint prominent.

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?

Covers purpose, precondition, fallback path, and the resulting state change ('Effects: entry voided'), which is sufficient given there is no output schema and only two fully documented parameters. Nothing an agent needs to call this correctly is missing.

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 coverage is 100%, with both entry_id and reason documented in-schema, so the description only needs to reinforce. It mentions 'with a reason' but adds no format or validation detail beyond what the schema already provides — baseline 3 is appropriate.

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 verb and resource ('Void an adjusting entry') plus the scope constraint (open period, with a reason), which cleanly separates it from gl_record_entry and gl_close_period. An agent can identify the operation without opening the schema.

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 an explicit precondition ('Only while its period is open') and a named fallback behavior for the excluded case ('In a closed period, record the opposite entry in the open period instead'). This is exactly the when-to-use / when-not-to-use guidance that prevents a wrong call.

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