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

Annotations already declare readOnlyHint=true, openWorldHint=false and destructiveHint=false, so the safety profile is covered. The description usefully expands on what is actually returned (handoff state, custom fields), but says nothing about permissions, rate limits, or behavior for a missing/invalid id. Adding field coverage beyond the annotations earns a solid 3.

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?

Two tight sentences: the first front-loads the core action and returned fields, the second is a single routing pointer. No filler or restatement of the title.

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 no output schema, the field enumeration does real work in telling the agent what comes back, and the pointer to list_messages correctly prevents the agent from expecting message bodies. It could be slightly more complete about absent/invalid id behavior, but for a simple single-id read it is nearly sufficient.

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?

With a single parameter at 100% schema description coverage, the schema already documents the id and its `cnv_…` format and origin. The description adds no syntax or sourcing detail beyond that, 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 ('Read one conversation') and then enumerates the exact fields returned (subject, status, priority, customer, assignee, team, topics, channel, handoff state, custom fields). This distinguishes it cleanly from find_conversation (search) and list_messages (message retrieval), both of which appear in the sibling list.

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 routes the agent to list_messages for message content, which is a genuine when-to-use-elsewhere signal, and the schema notes the id comes from find_conversation. It stops short of stating exclusions (e.g., that this does not fetch orders or messages), so it is clear context without full alternative coverage.

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