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

Annotations already declare readOnlyHint=true, openWorldHint=false, and destructiveHint=false, so the safety profile is covered structurally. The description adds genuine value beyond that: credentials are managed externally, and the output IDs are the input keys for other MCP tools, which is behavioral context the annotations cannot convey.

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 sentences, nothing wasted. The core purpose is front-loaded, followed immediately by the operational constraint and the use of the result.

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 trivial no-argument list tool with no output schema, the definition covers purpose, the external setup prerequisite, and the purpose of the returned IDs. A brief note on what each source record contains (id, name, type) would close the only real gap, but the entry is adequate as written.

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?

The tool takes zero parameters and schema coverage is 100%, so the schema fully documents the (empty) input. Per the baseline for zero-parameter tools, no compensating prose is required, and the description correctly does not invent any.

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 ('List saved external DB sources') plus the scope ('for the organization'), so the agent knows this is a read-only inventory operation. It does not explicitly distinguish itself from nearby siblings like nexusai_db_services_list or nexusai_managed_db_list, which a reader must infer.

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 when-to-use context and an implicit when-not: connection registration and credential configuration happen outside chat via the dashboard or REST API, not through this tool. It also explains the downstream purpose of the result ('use the returned source IDs with MCP tools'). No explicit exclusions against sibling list tools, but the context is solid.

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