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

Annotations already declare readOnlyHint=true, destructiveHint=false, and openWorldHint=false, so the safety profile is covered. The description usefully discloses the returned fields (unit, latest reading, open-decision count), which matters since there is no output schema, but says nothing about pagination, ordering, or empty-state behavior.

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 tight sentences, front-loaded with what the resource is before the usage triggers. Slightly literary phrasing ('the numbers the workspace watches') costs a little precision but no real bloat.

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 carries the burden of describing the return shape and does so adequately (unit, latest reading, open-decision count). Combined with fully covered schema parameters and read-only annotations, an agent has enough to call it correctly; pagination/ordering details are the only real omission.

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 workspace parameter is thoroughly documented in the schema itself (default handling, API-key behavior). The description adds no parameter-level information, so the 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?

The description characterizes the resource well (tracked metrics, each with unit, latest reading, and bound-decision count), which tells an agent what this returns. It is slightly indirect — it never uses a list verb and does not explicitly distinguish itself from ledger_metrics_get or ledger_metric_presets_list — but the title plus the payload description make the intent 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?

Gives two concrete triggers: when a user mentions a number that sounds like a tracked metric, and before recording a reading (an implicit check-before-write rule). No alternatives are named, but the when-to-use conditions are specific and actionable.

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