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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint=false, covering the safety profile. The description adds behavioral context by stating it 'Returns the full connection record' and that the ID is 'obtained from `list_unified_connections`', which provides useful provenance. It does not contradict annotations, and while it doesn't detail error handling or auth, the read-only nature is adequately covered by annotations plus the description's clarity.

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?

The description is two sentences with no redundant words. It leads with the primary action, then provides the return behavior and usage guidance. Every sentence earns its place, and the structure is front-loaded with the core purpose.

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 single-parameter read-only retrieval tool with no output schema and no nested objects, the description is complete. It explains what the tool does, when to use it, where to get the required ID, and what the return value is. Nothing essential is missing for an agent to call 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?

Schema coverage is 100% since the only parameter `id` has a description. The description adds value beyond the schema by specifying that the ID comes from `list_unified_connections`, which helps the agent understand where to obtain valid input. This is meaningful supplementary information beyond the schema's bare definition.

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 action ('Retrieve a single connection by its ID'), the resource ('connection'), and the scope ('from the connected account'). It also distinguishes itself from the sibling list tool by explicitly naming `list_unified_connections` as the alternative for searching or listing, making the purpose unambiguous.

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?

The description gives explicit usage guidance: 'Use when you already have the ID; to search or list connections, use `list_unified_connections`.' This directly tells the agent when to invoke this tool versus the alternative, leaving no ambiguity.

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