heroku_config_vars

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

No annotations are provided, so the description carries the full burden of behavioral disclosure. It mentions the tool can 'Get or set' config vars, implying both read and write operations, but doesn't specify permissions required, whether changes are reversible, rate limits, or what happens on success/failure (e.g., response format). This is a significant gap for a tool with mutation capabilities and no annotation coverage.

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, efficient sentence that front-loads the core functionality ('Get or set config vars') and specifies the resource ('for a Heroku app'). There is zero waste or redundancy, making it appropriately sized and easy to parse quickly.

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?

Given the tool's complexity (handles both read and write operations with 4 parameters), lack of annotations, and no output schema, the description is incomplete. It doesn't cover behavioral aspects like mutation effects, error handling, or return values, leaving gaps that could hinder an AI agent's ability to use the tool correctly in varied contexts.

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 100%, so the schema already documents all four parameters (appName, set, key, value) with clear descriptions. The description adds no additional meaning beyond what the schema provides, such as explaining interactions between parameters (e.g., how 'set' toggles behavior) or usage examples. Baseline 3 is appropriate when schema does the heavy lifting.

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 clearly states the tool's purpose as 'Get or set config vars (environment variables) for a Heroku app,' which includes a specific verb ('Get or set') and resource ('config vars for a Heroku app'). It distinguishes from siblings like 'heroku_get_app' or 'heroku_list_apps' by focusing on environment variables, but doesn't explicitly differentiate from potential overlapping tools (e.g., if there were a 'heroku_get_config' sibling).

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 alternatives. It doesn't mention prerequisites (e.g., needing the app name), when to prefer this over other config management tools, or any exclusions (e.g., not for app-level settings). Usage is implied through the parameter 'set' but not explicitly stated in the description text.

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