add_replica

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

With no annotations, the description carries the full burden. It does disclose a genuinely important side effect — MongoDB and MariaDB primaries restart once on the first add — which is real added value. However, it says nothing about permissions, whether the operation is asynchronous, idempotency, or failure modes.

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?

A single sentence that front-loads the action, then the placement detail, then the risk caveat. No filler, though the parenthetical placement syntax is slightly compressed relative to its importance.

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 2-param mutation tool with no annotations and no output schema, the description covers purpose, placement shape, and the most surprising operational consequence. Remaining gaps (async behavior, permissions) are secondary but real.

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?

At 50% schema coverage the description must compensate, and it partially does: it enumerates the placement keys {node, region, labels}, which the schema leaves as an untyped empty object. But it does not explain the semantics of each key (mutually exclusive? precedence? format of labels).

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?

Specific verb+resource ('Add a read replica to a database') with the placement dimension named inline. It distinguishes itself naturally from list_replicas and promote_replica, though it never explicitly contrasts with them.

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 the tool name and the 'on a given server or region' phrasing, but there is no explicit when-to-use/when-not guidance or reference to alternatives like promote_replica or list_replicas for verification.

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