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

With no annotations, the description carries the full burden and does so well: it discloses irreversibility, the 409 refusal on replace/discard, the reverse-and-leave-both-visible recovery path, and the single in-place exception (guessed-account on a coding_guessed entry). This is exactly the failure mode an agent would otherwise trigger.

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 action and its 'One-way' warning, then three tight sentences on consequences. Slightly heavy use of code-path fragments ('…/reverse', 'PUT …/guessed-account') and 'ZET-159'-style references outside the description, but no wasted prose.

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?

For a mutation tool with no annotations and no output schema, the description covers the important danger zone (irreversibility, error codes, recovery). It stops short of stating auth/role requirements beyond the word 'accountant' and never describes what posting returns.

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?

Top-level schema description coverage is 0% and the description mentions none of entry_id, company_id, or the body flags. The nested body properties (not_vat, allow_untagged_control, confirm_bank_duplicate) are documented in the schema only, and the description never connects them to the error paths it warns about — so it fails to compensate for the coverage gap.

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+resource ('Post a draft entry into the books') and immediately pins it to a role ('accountant') and a one-way nature. That plus the reference to '…/reverse' cleanly separates it from create_gl_journal_entry (draft creation), get_gl_journal_entry (read) and reverse_gl_journal_entry (correction).

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 clear operational context: verify the draft first because posting is irreversible, and reserve the guessed-account PUT for one specific case. It does not explicitly name create_gl_journal_entry as the precondition tool, so the routing to the correct sibling for drafting is left to inference.

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