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

Annotations already declare destructiveHint=true, idempotentHint=true, and readOnlyHint=false, so the safety profile is covered. The description adds genuinely new behavioral guardrails in the form of the reserved-path exclusion and the single-Hono-route restriction. It stops short of stating whether omitted fields are preserved (partial vs. full replacement) or how destructive the change is.

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 zero filler: the mutation scope comes first, followed by the structural and path constraints. Every sentence carries information an agent can act on.

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?

With a fully documented schema, an output schema, and rich annotations, the description covers the essentials plus two important guardrails. The one remaining hole is whether this is a partial patch (fields not supplied left untouched) or a replacement, which matters for a destructive, idempotent mutation.

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 the schema already documents all five parameters, including the enum for method and the path format. The description only mirrors the three mutable fields (source, path, method) in prose and adds no syntax, format, or interaction detail beyond the schema, so the baseline 3 applies.

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 and resource ('Change an endpoint's source, path, or method'), which lets an agent distinguish it from projects_cloud_endpoint_create and projects_cloud_endpoint_get. It does not name sibling tools explicitly, so it falls 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 description gives a real when-not constraint ('Do not point it at login, signup, or /auth') and a structural constraint ('One Hono route only'), which is useful. However, it never says when to prefer this over cloud_endpoint_create or cloud_endpoint_get, nor when an update is required rather than a republish, so usage is only partially implied.

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