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 the operator-key auth requirement and the partial-merge semantics, both of which are genuinely useful. It says nothing about what happens to an unknown endpoint_id, whether changes are reversible, or what the response contains, leaving real gaps for a mutation tool.

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 sentences, no waste, with the scope and the mutation behavior front-loaded before the auth caveat. Every sentence adds information an agent needs.

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 mutation tool with no annotations, no output schema and 8 undocumented parameters, the description covers purpose, auth and partial-update behavior but not error conditions or header/timeout formats. An agent could invoke it, but would be guessing on several parameters.

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% across 8 parameters, so the description must compensate and only partly does: it names name, description, price and a loose 'upstream' that maps to four distinct parameters. It gives no format for upstream_headers (a nested string map), no range or default for upstream_timeout_ms, and never explains endpoint_id.

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 ('change') plus resource ('one of your gateway endpoints') and an explicit seller-side scope, which separates it from gateway_catalog and gateway_probe. It lists the mutable fields, but never names a sibling such as gateway_register, so the create-vs-update boundary is inferred rather than stated.

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?

'Seller side' and 'REQUIRES OPERATOR KEY' give the caller the precondition up front, and 'Only the fields you pass change' tells the agent this is a partial update rather than a full replace. There is no explicit when-not guidance or mention of alternatives like gateway_register or gateway_pause.

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