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

Annotations (readOnlyHint=true, idempotentHint=true, destructiveHint=false) already convey that this is a safe, non-mutating read-only operation. The description adds no additional behavioral context beyond saying it lists, and it does not mention whether results are ordered, paged, limited, or filtered. With annotations covering the safety profile, a score of 3 is appropriate.

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?

The description is a single, front-loaded sentence: 'List all available context souls.' It states the verb and resource concisely with zero wasted words, which achieves appropriate size and clarity for a zero-parameter list tool.

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-parameter, read-only tool with a trivial schema, the description nearly suffices. The only omission is clarifying what a 'context soul' is and how many of them might be returned, but given the tool's simplicity and the safety annotations, the definition is fairly complete.

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 has zero parameters, and Baselines we set the baseline for a 0-parameter tool at 4. Although the description adds no parameter-specific semantics, the absence of parameters means there is nothing meaningful to document and the 100% schema description coverage (or equivalent) means nothing remains undocumented. This deserves the baseline 4 rather than a high parameter-related score since the description itself offers no parameter detail.

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 says 'List all available context souls' which names a specific verb and resource, so it is clear about what the tool does. However, it does not distinguish this from sibling tools like list_tags or get_soul beyond the resource name, and 'context souls' is somewhat domain-specific jargon that may not be immediately informative without additional context.

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 description provides no guidance on when to use this tool versus siblings such as get_soul, list_tags, search_by_tag, or generate_faf_from_github. There is no mention of what 'context souls' means, nor any context indicating whether this is a discovery tool, a navigation tool, or a retrieval tool. An agent would have to infer usage from the tool name and schema alone.

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