Elder Futhark List

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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint=false, so the safety profile is covered. The description's genuine addition is the cost disclosure ('10 credits (Tier 1)') and the endpoint, which the agent can't get elsewhere — but it says nothing about whether the payload is static reference data or what shape the list takes, beyond what the output schema carries.

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?

'All 24 runes' is front-loaded and the metadata brackets are compact, so there is no wasted prose. The bracketed group/endpoint/cost block is machine-ish padding rather than descriptive text, which slightly dilutes an otherwise tight definition.

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-argument catalog lookup with an output schema and complete annotations, the description supplies enough to call it correctly. The cost line is a useful extra; only a note on whether the returned entries include meanings/keywords is missing, and the output schema partly fills that.

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 per the rubric this hits the baseline 4. There is nothing parameter-related the description needs to explain, and schema coverage is 100%.

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?

'All 24 runes' plus the 'Elder Futhark List' title makes it clear this returns the complete reference set of 24 runes rather than a draw. That distinguishes it reasonably from siblings like astroway_runes_single, runes_three, and runes_nine, though the verb is implicit (no 'returns/lists').

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?

There is no statement of when to use this instead of astroway_runes_single, astroway_runes_three, astroway_runes_nine, or runes_by_zodiac. An agent must infer from the name alone that this is the full-catalog lookup rather than a casting tool.

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