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

Annotations already mark the tool read-only, idempotent, and non-destructive, but the description adds important behavior beyond that: it surfaces dates quoted from messages along with the originating message and sender, and warns that those dates are the sender's words rather than court orders. It also reveals that attachments are included and that senders can include anyone the user gave the address to.

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 description is front-loaded with the core read action and then moves to usage guidance glasnost. The date-surfacing explanation is somewhat long but earns its place because it is a distinctive behavioral trait. It is not maximally tight, but every sentence serves tool selection or invocation.

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?

Between the 100%-documented schema, the rich annotations, and the description, an agent has what it needs to select and call the tool correctly: content, senders, attachments, date-surfacing behavior, use cases, and a clear boundary against the user's own inbox. There is no output schema, but the description adequately summarizes what the tool returns, including quoted dates with source messages and senders.

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?

The input schema provides 100% description coverage for all four parameters, including defaults and matching behavior, so the schema already carries the parameter documentation burden. The description adds contextual framing about case correspondence but no additional parameter-level semantics, matching the baseline of 3.

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?

The description names a specific action and resource: reading correspondence delivered to a saved case's CaseMail address. It enumerates senders and attachments artist-spec, and the closing contrast with the user's own inbox clearly separates it from sibling tools like get_case_updates and get_case_deadlines.

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 explicitly gives trigger conditions: when the user asks what someone emailed about the case, what correspondence arrived, or to find a message about a subject. It also cautions that this is case correspondence, not the user's own inbox, and clarifies that surfaced dates are not court orders, preventing confusion with get_case_deadlines.

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