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

Annotations already declare the safety profile (not read-only, not idempotent, not destructive), so the bar is lower, yet the description still adds real behavioral context: patch semantics ('only the fields you pass change'), empty-value clearing, and the delivery-affecting side effect of mode/disable changes. It does not cover permission requirements or error 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?

Three sentences, all load-bearing: the action, the patch/clear semantics, and the side effect plus verification route. Front-loaded with the core verb and no filler.

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 14-parameter mutation tool with no output schema, it covers the critical semantics (patch behavior, clearing, delivery impact, verification path). Minor gaps remain around validation failures and how priority interacts with other routes, but nothing essential to a correct call is missing.

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 cross-parameter semantics the schema only states per-field: the patch contract that unspecified fields are untouched and explicit empties clear filters, with a concrete severity example. This meaningfully reduces misuse risk beyond the schema.

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 ('Update one notification route in place') with a scoping qualifier ('one') that separates it from create_notification_route, delete_notification_route and the list sibling. An agent can identify this as the in-place mutation tool without opening the 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 clear context for use (patching an existing route) and names an explicit follow-up alternative, preview_notification_routing, with the condition that triggers it (mode/disable changes). It stops short of stating when NOT to use it, e.g. creating a new route or bulk changes.

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