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

Annotations already declare destructiveHint=true, yet the description still adds real context: the mechanism (counter-entry, not deletion), that the original remains in the ledger, and that only API-created entries qualify. These are consequences an agent cannot infer from the safety hints alone.

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?

Three short clauses with the danger marker front-loaded and zero filler. Every sentence carries a distinct constraint: irreversibility, mechanism, eligibility, confirmation.

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?

With no output schema, the description does not say what comes back (e.g., the new counter-entry's id), and it omits any date/period considerations. Otherwise it covers everything needed to invoke a single-parameter destructive tool safely.

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% and the single parameter carries a description plus GUID pattern, so the schema fully documents it. The description adds nothing about journalEntryId, which is the expected baseline when the schema does the work.

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 mechanism ('post a counter-entry that cancels a journal entry'), not just a verb+resource, which distinguishes it from bokio_create_journal_entry and bokio_get_journal_entry. The leading 'IRREVERSIBLE' tag further disambiguates it from the read/list siblings.

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?

Explicit when-to-call ('Only call when the user has confirmed') and an eligibility precondition ('Only entries created through the API can be reversed'). It does not name an alternative path for non-API entries or suggest verifying state first, so it stops short of the top band.

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