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

Beyond the annotations (which only assert readOnly=false/destructive=false/idempotent=false), the description discloses the match-resolution rule (one match stopped, several listed and none stopped), the session-scoping limit (another session's watch is never found), and that results carry an attribution line. These are the behaviors an agent cannot get from the structured fields.

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 effect, then usage, then exclusions, then fallback behavior. Dense and largely waste-free, though the kind/key enumeration in the prose partially duplicates the schema and the parenthetical example clusters lengthen it.

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 stateful mutation tool with no output schema, the description covers purpose, trigger conditions, alternatives, ambiguous-match handling, cross-session limits, and the attribution of results. An agent has everything needed to call it correctly or choose a sibling instead.

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 description coverage is 100%, so the baseline is 3, but the description adds a genuine decision heuristic for the alternative invocation paths — id vs. kind+key — and notes that the key is matched case- and space-insensitively against this session's open watches. It does not, however, explain anything about `uri` or `language` beyond what the schema already says.

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?

Names a specific verb (ends/stops) and resource (a watch opened by watch_situation) plus the consequence (no further notifications). It explicitly distinguishes itself from watch_situation (create), check_road_status (lookup) and viafrei://watches (listing), so an agent can route correctly without reading any sibling 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?

States when to use it with natural-language user examples ("du musst mir nichts mehr zur A8 sagen"), gives explicit negative cases (do NOT look up, list, or cancel outside this chat), and explains the no-id fallback path (kind + key in the person's words) including the ambiguous-match outcome. 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.