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

With no annotations, the description carries the full behavioral burden. It usefully discloses partial-update semantics ('only provided fields', 'does not clear omitted fields') and a hard restriction ('coordinates cannot be changed'), which is real added value for a mutation tool. However it says nothing about permissions/auth, reversibility, or error behavior when the code is invalid.

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?

Three short, front-loaded sentences with no filler; the most important constraint (partial update, omissions preserved) leads. Slightly terse given the scope, but nothing is wasted.

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?

A nested 15-field mutation object with no annotations and no output schema warrants more disclosure than provided. Update semantics are covered, but the identifier parameter, authentication expectations, and what a successful patch returns are all missing.

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 0%, so the description must compensate. It gives one example field ('instructions') and the crucial semantics of omitted keys in the changes object, which is genuinely helpful. But the required 'code' parameter is never explained and the remaining ~14 updatable fields are left to schema names alone.

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 (patch) and its defining behavior: only provided fields are updated. Combined with the tool name, an agent can tell this apart from create_address/delete_address/list_addresses, but it never names those siblings or explicitly says it modifies an existing address record.

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?

No when-to-use guidance and no explicit routing to alternatives. The reader must infer from the word 'patch' that this is the partial-update path versus create_address or delete_address; nothing in the text establishes that.

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