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

Discloses key behaviors beyond the annotations: GROW-ONLY semantic, online operation with no restart, and the requirement that storage_gb must come from specific reported sizes. No contradiction with annotations.

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 front-load the purpose, then constraints; no filler. Every sentence earns its place.

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?

Covers purpose, trigger, constraints, operational behavior, and preconditions. No output schema needed; the description adequately prepares the agent for invocation.

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 already provides full descriptions for app_id and storage_gb; the description reiterates the grow-only constraint but adds the 'fit your storage pool' requirement, offering minimal extra value 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?

The description clearly states the verb 'Grow' and the resource 'the disk of an app's managed database', distinguishing it from sibling tools like resize_database by focusing on storage/disk. The title reinforces this.

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?

Provides an explicit trigger ('Call this when the database is running out of disk space') and a precondition ('Only works if the app has a managed database'), but does not name alternative tools for different resize scenarios.

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