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

Annotations already establish readOnlyHint=true and openWorldHint=false, so the safety profile is covered. The description goes beyond that by disclosing the return contents in detail: every inbound/outbound message with delivery status (sent, delivered, opened, bounced, not sent and why) plus email-capability of the contact.

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?

Single front-loaded sentence led by the core action 'Show one conversation in full'. It is densely packed with em-dash asides, but every clause (lookup keys, message detail, email capability) adds information rather than repeating structured fields.

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 description must convey what comes back, and it enumerates the message fields and delivery statuses plus email eligibility. It does not mention pagination or volume limits for long threads, a minor gap for a tool that 'shows everything'.

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 coverage is 0%, so the description must carry parameter meaning, and it does: conversation_id selects by conversation, contact_id selects that contact's whole thread. This explains the semantics and the choice between the two optional parameters beyond what the bare schema provides.

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 (Show) and resource (one conversation), with explicit scope 'in full'. This clearly distinguishes it from crm_inbox (a list) and crm_update_conversation (a mutation) without needing to open either 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?

It clarifies how to look up the conversation — by conversation_id or by contact_id for that contact's thread — which is useful invocation guidance. However, it never states when to prefer this tool over siblings like crm_inbox or crm_contact_channels, so alternative routing is left to inference.

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