gmail.users.threads.delete

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

With no annotations provided, the description carries the full burden and does well: it discloses cascade destruction ('any messages ... are also deleted'), irreversibility, refusal under --readonly safety profiles, and the shape of the response. The generic claim that it 'returns the post-delete resource state (or empty)' is hedged and partly boilerplate, which keeps it just short of 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?

The destructive-scope and prefer-trash guidance is front-loaded in the first three sentences, which is exactly right. The trailing [HTTP DELETE] block and the request-body construction notes are generic boilerplate that adds no value to a bodyless deletion endpoint.

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 destructive, non-recoverable operation with no annotations and no output schema, the description covers scope, reversibility, sibling alternatives, and the return value — everything an agent needs to decide and invoke safely. It stops short of stating required OAuth scope or quota, which a fully complete definition would mention.

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 both required path segments (userId, id) are already documented, and the description adds nothing about them. The only added semantics is the precedence rule that typed flags win over the `params` map and that `body_file` overrides body construction — useful but largely irrelevant for a bodyless DELETE.

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 ('permanently deletes the specified thread') and immediately extends the scope to cascading deletion of contained messages. It also names the sibling resource operations (get, list, modify, trash, untrash) at the end, so an agent can distinguish it from threads.trash and messages.delete without opening the 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?

Explicitly routes the agent: 'Prefer `threads.trash` instead' names the alternative and the condition (recoverability) that selects it. The irreversibility warning supplies the when-not case, and the readonly-profile note tells the agent under what execution context the call will be refused.

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