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

Annotations already declare readOnlyHint=true and openWorldHint=true, so the safety profile is covered. The description adds genuine value by enumerating what a successful response contains (name, subject, preview text, sender, reply-to, recipients, delivery moments, web version URL) in the absence of an output schema; it does not cover error behavior (e.g. unknown campaign_id) or auth requirements.

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 front-loaded sentence with the verb and resource first, then the field list. The enumeration is long but earns its place since no output schema exists; nothing is redundant.

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 single-parameter read tool with annotations covering safety and no output schema, describing the returned fields is the key missing piece and it is present. Minor gaps remain around error cases and how to obtain a valid campaign_id, but the description is sufficient to call the tool correctly.

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 parameter already documents its source (laposta_list_campaigns), so the description adds nothing beyond the schema. Baseline 3 applies when the schema does the heavy lifting.

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 ('Get one campaign') and enumerates the fields returned, which implicitly separates it from laposta_get_campaign_content and laposta_get_campaign_history (which cover body content and history respectively). Siblings are not named explicitly, so it stops short of a 5.

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 only implied: an agent infers it should call this when it needs campaign metadata, and the schema's parameter description ('from laposta_list_campaigns') hints at the discovery path. There is no explicit when-to-use versus get_campaign_content/get_campaign_history guidance or exclusion.

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