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

Annotations only state readOnly=false/destructive=false/idempotent=false. The description goes well beyond: credentials are encrypted and never returned yet transit the conversation (a real security caveat), and unclaimed workspaces are refused with 403 until a person claims them. That is exactly the failure-mode and side-effect context 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?

Four dense sentences, purpose front-loaded, no filler. The prerequisites and credential warning are packed tightly, though the security caveat and the 403 rule could be split for easier scanning.

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 mutating 4-param tool with nested objects and no output schema, the description covers auth, scope, credential handling, and a specific failure code. The only notable gap is what happens on a duplicate/already-linked store, though idempotentHint=false partially covers it.

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%, so baseline is 3, but the description adds real semantics: the valid value space for `platform` comes from list_commerce_connectors, `credentials` is write-only and sensitive, and `metadata` controls competitor price sourcing. That exceeds what the schema text says.

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?

Opens with a specific verb+resource: 'Link a store to the commerce pipeline', and names the sibling that supplies valid platform values (list_commerce_connectors). An agent can distinguish this from sync_commerce_connector or set_commerce_connector_active without opening a schema.

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 concrete preconditions for use: owner/admin role, a Last Price credential with commerce configure scope, and a claimed workspace, plus the routing to list_commerce_connectors for platform values. It stops short of explicitly naming when not to use it (e.g., when a connector already exists, use sync_ instead), so not a full 5.

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