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

Annotations already establish read-only, idempotent, non-destructive behavior, and the description adds genuinely non-obvious state-machine semantics: DEPLOYING with ready_at set means the new version is already reachable, it transitions to RUNNING once confirmed, or to ERROR with an error_message on crash. That is a meaningful behavioral disclosure beyond the annotations, though it says nothing about freshness, caching, or polling expectations.

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, each earning its place: purpose plus return fields first, use cases second, state-lifecycle nuance third. Nothing is padded and the most decision-relevant information is front-loaded.

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 fully carries the burden of describing return values and does so explicitly. For a one-parameter read tool with strong annotations, an agent has everything needed to select and invoke it correctly.

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?

There is a single parameter with 100% schema description coverage, so the baseline is 3. The description supplies no additional semantics about app_id (formats, where obtained), leaving the schema to carry it.

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 ('Get detailed status for one app') and enumerates exactly what is returned: deploy status, URL, last deployed commit, and error message. This distinguishes it from siblings like get_app_logs and list_apps without needing to open either 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 three concrete use cases: checking whether a deploy finished, retrieving the live URL, and diagnosing an error state. It is strong context but stops short of naming the alternatives (e.g. use get_app_logs for stack traces) or stating when not to use it, so it does not reach a full 5.

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