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

Annotations already declare readOnlyHint, idempotentHint, non-destructive, and closed-world, so safety is covered without the description. The description adds return-shape detail (each item has a ready-to-paste `expr` and optional `note`) and the no-key fallback behavior, which is genuine added value. It says nothing about permissions, error behavior, or whether slot keys must already exist, so a 3 rather than a 4.

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 tight sentences, front-loaded with what the tool returns, then the keyed mode, then the unkeyed fallback — a sensible discovery order. Minor waste in the parenthetical product reference ("when selieeslave renders it") and the editor "info" panel aside, which add flavor more than operational value.

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-optional-parameter read tool with full annotations and no output schema, the description covers both invocation modes and the shape of returned items, which is enough to call it correctly. What is missing is only edge-case behavior (invalid/unknown slot key, whether output is paginated or complete), which is low-stakes here.

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 0% and the schema is a bare nullable string, so the description carries the full load and mostly does: it explains the argument is a slot key, gives concrete example values (`articles`, `index`, `robots`, `llm`), and defines the default behavior when omitted. The only gap is that the parameter is named `seliee_template_key` while the prose calls it a "slot key," leaving the exact relationship between template key and slot key unstated.

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: it returns the Jinja variables each template slot receives, and anchors this to a recognizable surface (the editor's "info" panel). An agent can tell what it produces without opening the schema. It does not, however, distinguish itself from near-neighbors like get_template, get_template_key, or get_rule_variables/get_image_variables, which an agent could easily confuse with it.

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?

Gives two explicit calling modes with conditions attached: pass a slot key to get that slot's variable groups, or omit it to enumerate available slot keys and group titles. That is clear usage context. It stops short of naming alternatives or stating exclusions (e.g., when to prefer get_template_key), so it is not a full when/when-not treatment.

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