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

Annotations already declare readOnlyHint=true, destructiveHint=false and openWorldHint=false, so safety is covered. The description adds real context beyond that: it returns the credit cost of one generation, and the cursor parameter implies paged template retrieval. It does not state the response shape or whether brands and templates are returned together or separately, which keeps it from a 5.

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 sentences, front-loaded with the core purpose and followed by the two resource definitions and the enum semantics. The templateSource sentence largely duplicates the schema wording, which is the only wasted space; otherwise every clause contributes.

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 read-only three-parameter list tool with no output schema, the description tells the agent what comes back (brands, templates, credit cost) and how the source toggle affects results, which is what an agent needs to call it and use the result. The only gap is that the pagination contract (using nextTemplateCursor from a prior call) is stated only in the schema, not the description.

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 description coverage is 100%, so cursor and workspaceId are already fully documented. The description restates templateSource in nearly the same words as the schema rather than adding new meaning, and says nothing about cursor or workspaceId defaults beyond what the schema carries. Baseline 3 is appropriate.

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 brands and templates in a workspace) and names the consuming sibling, create_carousel, so the agent knows exactly what the payload feeds. It also defines the two resource types inline (brands = name and logo on slides; templates = fixed design filled with new copy), which removes ambiguity.

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 framing 'what create_carousel can use' gives clear implied usage: call this before create_carousel to discover valid inputs. It also gives explicit selection guidance for the templateSource enum (posteady = default provider templates, workspace = locally saved). No explicit exclusions or 'do not call when' guidance, so it stops short of a 5.

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