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

Annotations already declare readOnlyHint=true, destructiveHint=false, openWorldHint=false, so the pure-transformation nature is covered. The description adds only that it returns the final prompt, but says nothing about the template variable syntax, where substitution values come from, or how 'state' influences resolution behavior.

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 no filler; the core action is stated immediately. It is efficient, though it is so terse that it omits necessary context rather than being maximally useful.

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?

With no output schema, a nested state object, and 3 parameters at 0% schema coverage, the definition should carry much more weight. It omits parameter roles, the template syntax, and return structure, leaving the agent unable to invoke it reliably.

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% across 3 parameters, including a nested 'state' object and the unexplained 'withSystemPrompt' flag. The description implies variables are replaced 'with values' (hinting at 'state') but never maps any parameter to its role, so it fails to compensate for the documentation 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-session prompt template') plus the outcome ('returns the final prompt'). The 'llm-session' qualifier distinguishes it from the sibling resolve_llm_reaction_prompt_template, though it never names that alternative explicitly.

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 only states what the tool does; it gives no when-to-use context, no prerequisites, and no indication of when to pick this over resolve_llm_reaction_prompt_template or how the resulting prompt should be consumed. The agent must infer usage entirely.

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