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

Annotations already declare readOnly, idempotent, non-destructive and closed-world, so the safety profile is covered. The description adds genuinely new context beyond them: it mirrors the woocommerce-mcp-server `get_order_meta` method and authenticates via local WordPress credentials rather than WooCommerce REST API keys, which matters for setup. It does not describe the return shape, so it is not a 5.

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, front-loaded with the core purpose, and the secondary sentence carries non-redundant authentication context. Nothing is padded, though the mirror-method clause is the least load-bearing part.

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 read-only getter with full schema coverage and no output schema, the missing piece is what comes back — notably whether supplying metaKey returns a single value versus a collection. Annotations cover the safety dimension, so this gap is the only real one, but it is a meaningful one for a retrieval tool.

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 description coverage is 100%, so all three parameters are already documented in the schema, including the site_id 'call list_sites first' caveat. The description only restates the optional metaKey filter and adds no format or semantics beyond the schema, which is the baseline-3 case.

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+resource pair ('Retrieves WooCommerce order metadata') and states the optional meta-key filter, which cleanly separates it from the meta siblings such as wc_get_customer_meta and wc_get_product_meta. It does not explicitly name a sibling or contrast behavior, so it stops short of a 5.

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 phrase 'optionally filtered by meta key' implies the two usage modes (full meta dump vs. single-key lookup), but there is no explicit when-to-use/when-not guidance and no pointer to wc_get_order or the update/delete meta siblings. Usage is inferable rather than stated.

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