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

Annotations already declare readOnlyHint=true and destructiveHint=false, so the safety profile is covered structurally. The description adds real value beyond that: ordering (most recently updated first), a hard cap of 100 with no pagination mentioned, and a read-scope requirement. It does not describe what a session record contains, which matters since there is no output schema.

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, front-loaded with purpose plus ordering and cap, then the scope exclusion, then the auth requirement. Nothing is redundant and every clause carries information an agent would otherwise have to guess.

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 zero-parameter list tool with no output schema, the description covers invocation well: what is listed, ordering, cap, and auth scope. What it omits is the shape of a returned session (identifiers, titles, timestamps), which the agent cannot learn from any other structured field, leaving a moderate gap.

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 tool takes zero parameters, so the baseline is 4 and there are no argument semantics to explain. The mention of 'max 100' usefully signals the result cap even though it is not a parameter.

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 ('list your iris chat sessions') and clarifies the ambiguous name by glossing iris as 'the conversational campaign builder'. It also scopes out the live turn as SSE outside this tool set. It stops short of naming a sibling such as get_campaign_chat_messages for retrieving messages within a session, so the session-vs-message distinction is only implied by nouns.

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?

Usage is implied: consult this to see your existing builder conversations, most recent first. The description adds useful boundary information (the live turn is not here) but gives no explicit when-to-use/when-not or named alternative tool for follow-up actions like fetching messages or deleting a session.

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