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

Annotations already cover the safety profile (readOnlyHint=false, idempotentHint=true, destructiveHint=false), and the description adds two pieces of context the annotations do not: that omitted fields are preserved, and that user confirmation is required before applying. It omits error behavior for an unknown search_key, keeping it short of 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?

Three short sentences, front-loaded with purpose, followed by the partial-update rule and the confirmation requirement. No filler; every clause carries information.

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 an output schema present, return values need no explanation, and annotations cover idempotency and safety. The description supplies the partial-update and confirmation semantics, but does not signal the prerequisite that the route must already be tracked or point to track_flight/stop_tracking_flight as the alternatives.

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 schema already documents search_key, the email/text flags, alert_rule enum values, and the target_price_usd total semantics. The description only names the categories of fields in prose, adding no syntax or constraint detail beyond what the schema provides; baseline 3 is correct.

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 states a specific verb and resource ('change how a tracked route alerts') and enumerates the mutable surfaces (alert rule, target price, email/text channels). It clearly distinguishes updating an existing tracked route from the sibling tools that create or remove one, though it never names those siblings explicitly.

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?

'Only the fields given change' and 'Confirm first' give real operational guidance about partial updates and confirmation, which is more than most definitions offer. However, there is no explicit when-to-use guidance relative to siblings like track_flight (add) or stop_tracking_flight (remove), so usage context is only implied.

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