gc_template

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

With no annotations provided, the description carries the full burden of behavioral disclosure. It explains the two actions at a high level but doesn't disclose what happens on failure, required prerequisites (e.g., whether message_id must be valid, whether block_json must match a specific schema), error behaviors, or side effects. The 'merge-field' concept is introduced (GC-2774) but not elaborated.

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 compact with a bullet-style structure that front-loads the two key actions. Each sentence earns its place, and the ticket reference (GC-2774) provides traceability. It's efficient without being under-specified, though the terse formatting style could be marginally clearer.

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?

This is a moderately complex multi-action tool with 7 parameters and nested objects, no output schema, and no annotations. The description covers the two action paths but omits critical details like expected object shapes for block_json/values, error handling, and what the placeholders output should look like. It's adequate for basic usage but leaves the agent to guess on real-world invocation.

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%, so the baseline is 3. The description adds value by mapping which parameters belong to which action (placeholders vs fill), but it doesn't elaborate beyond what the schema already states. Nested objects (block_json, values) aren't described in terms of expected structure or format, leaving meaningful gaps.

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 identifies two distinct sub-operations (placeholders and fill) with specific verbs and resources, making the tool's purpose clear. However, the title is null and the tool name 'gc_template' alone doesn't fully convey that it handles merge-field templating; the description compensates reasonably well.

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 implies when each sub-action is appropriate (placeholders to list available fields, fill to render), which gives the agent some guidance. However, it doesn't explicitly explain which sibling tools might be alternatives or when templating would NOT be the right choice, and the relationship to other gc_* tools isn't clarified.

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