Build a raw Image-Charts URL

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 adds meaningful context by stating that the URL is signed automatically when icac is provided and IMAGE_CHARTS_SECRET is set. It also implies a pass-through behavior ('raw parameters') without validation, which is useful. However, it does not disclose return format variations (e.g., what happens when format='png') or any error behavior, leaving some gaps.

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 two sentences with no wasted words. It front-loads the key concept ('Escape hatch for full control'), then provides the mechanism and an important behavioral note. Every sentence earns its place.

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?

The tool has 35 parameters, no output schema, and no annotations, so the description needs to cover more ground. It clearly explains the core behavior and signing, but it does not clarify how the 'format' parameter affects the output (url vs png vs both). This is a notable omission given that the schema includes a format param with enum values, and without an output schema the agent cannot infer the return structure. Thus, the description is adequate but not complete.

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?

The schema description coverage is 100%, so the baseline is 3. The description lists several example parameters (cht, chd, chs, chco, chxt, chxl, chm) but does not add new semantics beyond what the schema already provides. The mention of signing with icac is also present in the schema's parameter description, so the description adds no extra value for parameter understanding.

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 with a specific verb and resource: 'pass raw Image-Charts parameters ... and get the hosted image URL.' It also distinguishes itself from siblings by calling it an 'escape hatch for full control' and mentioning the signing behavior, which differentiates it from a high-level chart creation tool like create_chart.

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 phrase 'escape hatch for full control' implies this tool is for users who need to bypass higher-level abstractions and specify raw parameters directly. This provides clear context, but it does not explicitly mention when to prefer this over create_chart or list_chart_types, nor does it state when not to use it. The guidance is implied rather than explicit.

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