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

Annotations already declare non-destructive and idempotent behavior, so the bar is lower, yet the description still adds genuine value: 'Nothing is deleted and no email is sent' confirms the non-effect, and it discloses the observable side effect on list_inbox results. It omits any auth/permission requirements or confirmation that the change is reversible.

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 with zero filler, and the primary effect (inbox visibility) is front-loaded before the usage guidance. Every sentence earns its place.

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 two-parameter, non-destructive mutation with no output schema, the description covers effect, safety, and usage context adequately. It could be richer about reversibility and whether unarchiving restores prior inbox position, but nothing critical to correct invocation is 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 100%, so the schema already documents both conversationId and the archived boolean including its default. The description only implies the bidirectional archive/unarchive behavior ('or brings it back') without adding format or sourcing detail beyond the schema, so 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 (archive/unarchive) and resource (conversation/thread), and explicitly frames the effect against a named sibling: 'so list_inbox stops returning it.' An agent can distinguish this from redirect_thread or mark_deal without opening a 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?

Gives clear when-to-use guidance ('Use it once a thread is dealt with, so the inbox reflects what still needs attention'), which is strong contextual framing. It does not name the reverse alternative (unarchive) as a separate routing decision or list exclusions, so it falls just short of explicit alternatives.

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