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

Annotations already declare readOnlyHint=true, so safety is covered. The description adds genuine behavioral content beyond that by noting the response includes child items for a collective entry, but it says nothing about error behavior, missing ids, or permissions.

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?

Two short sentences with no filler, front-loaded with what the tool returns. The trailing endpoint reference is compact and harmless. Slightly terse rather than padded, which is appropriate here.

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 single-parameter read-only lookup with no output schema, the description covers the essential contract: fetch one entry by id and note that collective entries include their items. Only minor gaps remain, such as what a not-found id 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?

Schema coverage is 100% and the single id parameter is fully documented in the schema, including its provenance from cashctrl_list_journal. The description only restates "by id" and adds no format or boundary detail beyond the schema. 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 verb and resource (get a journal entry by id) and clarifies the scope: a single entry with its items for a collective entry. That scope detail distinguishes it from cashctrl_list_journal, though the sibling is not named explicitly. The phrasing "One book entry by id" is slightly awkward but unambiguous.

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?

Usage is implied by the id parameter and the fact that this is the singular counterpart to cashctrl_list_journal, but the description never states when to use this versus list_journal or the create/delete siblings. No prerequisites or exclusions are given.

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