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

Annotations already establish readOnlyHint=true, destructiveHint=false and closed-world scope, so the safety profile is covered. The description adds real behavioral context beyond that: the ~1-year maximum window between `from` and `to`, and the fact that results include decision spans and standalone dates with no decision. It does not mention result size or pagination, which matters for a year-wide window.

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?

One dense block, but front-loaded with the mode-selection rule before the details, and every clause carries information (return shape, window limit, filter intent, exclusion). Slightly long and could be split for readability, but there is little dead weight.

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 the work of explaining what comes back — decision spans and every dated item in the window — which is exactly what an agent needs to interpret results. The remaining gap is the absence of any note on result volume or pagination for a window that can span a year.

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%, so the baseline is 3, but the description adds genuine meaning: it establishes that `entryId` and `from`/`to` are alternative modes, restates the YYYY-MM-DD format with the range constraint, and gives `ownerUserId` a purpose ('what's mine this week'). That is more than the schema's terse 'Only items owned by this member'.

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 — reads the Ledger calendar or a single decision's plan — and spells out exactly what the two query modes return (decision spans plus every dated item, including standalone dates). It is clearly the read counterpart to ledger_plan_add/update/delete, but it never names those siblings, so the differentiation is implicit rather than explicit.

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 explicit routing between the two modes (`entryId` for one decision vs `from`+`to` for the calendar), names concrete situations it answers ('what's mine this week', 'find tomorrow's items to draft'), and adds a hard exclusion — never use it to compare or rank people's output. Nothing 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.