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

Annotations already declare readOnlyHint, idempotentHint and destructiveHint=false, so 'Rein lesend' is largely redundant. However, the description adds a genuine behavioral/cost signal absent from structured fields: aggregation is cheaper than pulling raw data via onto_report_json, which directly affects tool choice. No detail on output shape or aggregation granularity, so not a 5.

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?

Purpose and the alternative-routing advice are front-loaded and the core is three tight sentences. The trailing EN keyword dump ('report, chart, heatmap, map, dashboard, evaluation, export, statistics') is retrieval filler that does not help an agent decide or invoke, so it costs a point.

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 one-parameter, non-destructive read tool with full annotation coverage, the description covers what it returns conceptually (aggregates instead of rows) and when to prefer it. With no output schema, the actual structure of the returned metrics is undisclosed, which is the remaining gap.

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 there is a single required report_id parameter, so the schema carries the load. The description adds no meaning beyond it (e.g. what report_id refers to, whether aggregations are configurable), so 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+resource (compute report metrics — sums/averages rather than individual rows) and explicitly distinguishes itself from two siblings, onto_report_json (raw data) and onto_report_map_data (map display). An agent can route correctly without opening any schema.

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 an explicit when-to-use condition ('Nutze es, wenn du Zahlen brauchst statt Datensaetze') and names the alternatives with the condition that selects each (onto_report_json for raw rows, onto_report_map_data for maps). 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.