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

Annotations already declare readOnlyHint=true, destructiveHint=false, and closed-world, so the safety profile is covered. The description adds that this is a pure transform that returns the final prompt, but it does not disclose which template variable names are supported or how state/request values are bound into them, which is the core behavior an agent needs.

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?

A single front-loaded sentence with zero filler; the transformation and its return value come first. It is efficient, though arguably too terse given the tool's nested parameters.

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 nested 4-parameter tool with 0% schema descriptions and no output schema, the description is inadequate: it omits the shape of state/request, the effect of withSystemPrompt, and any indication of which template variables exist or what error occurs on unknown variables.

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% with four parameters, two of them nested objects (state, request). The description vaguely says 'variables ... with values' but never maps prompt, state, request, or withSystemPrompt to any template variable, so it fails to compensate for the schema gap.

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: 'Replaces template variables in a llm-reaction prompt template with values and returns the final prompt.' It is clearly distinct from generic read/write siblings by name, but it never explicitly differentiates itself from the near-identical sibling resolve_llm_session_prompt_template, leaving the agent to infer the reaction-vs-session scope from the name alone.

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 when-to-use guidance, no prerequisites, and no mention of the sibling resolve_llm_session_prompt_template, which is the obvious alternative an agent must choose between. The only signal is the implied 'resolve a template before use' flow.

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