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

Annotations already declare the safety profile (readOnlyHint=false, destructiveHint=false, openWorldHint=false), so the bar is lower, and the description clears it by disclosing what actually gets written (connection env vars) and the operational consequence that a redeploy is required. It stops short of saying whether existing env vars are overwritten or whether detach reverses it, so it is not fully complete.

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?

Two tight sentences, front-loaded with the core action and followed by the key caveat. Every clause earns its place with 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 small mutation tool with matching annotations and no output schema, the description covers the essential effect and the redeploy requirement. It leaves notable gaps: no mention of reversibility via detach, no statement about overwriting existing env vars, and no clarification of the required identifiers.

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 only 33%: envPrefix is documented in the schema while deploymentId and managedDatabaseId have no descriptions anywhere. The description mentions injecting vars into a deployment but adds no meaning about the two required IDs or how envPrefix renames the listed env vars, so it fails to compensate for the coverage gap.

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 gives a specific verb and resource mechanism: it injects connection env vars into a deployment, and even enumerates the env var names. That is clear, but it describes the implementation rather than the 'attach' concept and never names the natural inverse sibling nexusai_managed_db_detach, so an agent must infer the pairing.

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?

Usage is implied by 'into a deployment' plus the 'Requires redeploy' prerequisite, which is genuine guidance about when the effect materializes. However, there is no explicit when-to-use statement, no when-not-to-use, and no routing to alternatives such as detach.

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