Select Stat Block

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

Annotations already communicate mutability and destructiveness, so the bar is lower. The description adds useful behavioral context by stating it stores only the Stat Block id in the MCP session, which clarifies the scope of state change. No contradiction with the annotations is present.

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?

Two short sentences accomplish the task: the first states the primary action and context, the second clarifies the precise persistence behavior. There is no filler or repetition.

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 simple two-parameter selection tool with an output schema and rich annotations, the description is nearly complete. It could optionally mention the expected workflow position, but the schema already supplies the key prerequisites, so nothing essential is missing.

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 both parameters already have rich descriptions: statBlockId is sourced from list_stat_blocks and playSessionId is tied to create_play_session. The description itself adds no parameter-level detail, so the baseline of 3 applies.

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 uses a specific verb ('Select') and resource ('SRD Stat Block'), and adds the context 'for the battle session' and the side effect of storing only the id. This clearly distinguishes it from browsing tools like list_stat_blocks or inspection tools like inspect_catalog_unit.

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 phrase 'for the battle session' gives clear context for when this tool applies, and the side-effect clarification helps distinguish selection from mere listing. It does not explicitly name alternatives or exclusions, but the intended use case is evident from the description and sibling context.

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