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

Annotations already declare readOnlyHint=true, destructiveHint=false and openWorldHint=false, so the safety profile is covered. The description adds value beyond that by disclosing the shape of the result (campaign, join link, participants with ids), which matters because no output schema exists. It does not say what happens when the campaign_id does not exist.

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?

One dense sentence with zero filler; the primary subject (the campaign) is front-loaded and the cross-tool pointer comes last where it is least disruptive.

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 one-parameter read tool with no output schema, the description covers the essentials by describing what comes back and how the ids are reused. Minor gaps remain around not-found behavior and whether the participant list is truncated, but nothing an agent needs to call it correctly 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 coverage is 100% and the single campaign_id property is already documented as 'The campaign's id (the id in list_campaigns)'. The description adds no further meaning about the parameter, 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?

The description names the resource precisely ('One hashtag campaign') and enumerates the payload: the join link and the participants with their ids. This clearly separates it from the list-oriented sibling list_campaigns, though it never uses an explicit verb like 'retrieve' or 'fetch'.

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 gives concrete downstream context by saying the returned participant ids feed remove_campaign_participant, which tells an agent why and when to call this tool. It stops short of explicit exclusions (e.g. 'use list_campaigns to discover the id'), so it is clear context rather than full when/when-not guidance.

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