hpe_fill_slots

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

With no annotations, the description carries the full behavioral burden and does so well: it discloses overwrite-via-atomic-replace when output_path is omitted, wrapping behavior, font auto-scaling, and that the output contains only answers. It stops short of failure modes or how invalid slot IDs are handled.

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?

Front-loaded with the core action and then an Args list, so it is easy to scan. The repeated emphatic '100% ... zero ...' guarantee phrasing is slightly padded but each line does convey a distinct behavioral trait.

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 4-param mutation tool with an output schema, the description covers the action, every parameter, and the return shape ('status JSON with saved path'). The main omission is any tie-breaking against the near-identical sibling tools.

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%, yet the Args block documents all four parameters, including that page_number is 1-based and that output_path is optional with atomic-replace semantics. The slot_answers_json entry adds concrete JSON examples covering plain strings, multi-line arrays, and a special key, far exceeding the bare schema.

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 ('Inject answers into the PDF using Slot IDs') and shows the data shape immediately. However, it never distinguishes itself from the very similar sibling hpe_snap_fill, so an agent must infer the difference without help.

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?

Usage is implied by the description (fill slot IDs on a given page) but there is no explicit when-to-use or when-not guidance, and no routing to alternatives such as hpe_snap_fill or hpe_render_verify. The agent is left to infer selection.

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