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

With no annotations, the description carries the full behavioral burden. "Fetch" implies a read-only operation and the description names returned components, but it does not disclose return ordering, rate limits, data source behavior, or error conditions.

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 front-loaded sentence with no wasted language. It identifies the indicator and the main returned components immediately.

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 10-parameter tool with fully described schema fields, the description is mostly complete enough to identify and select the tool. Because there is no output schema, it could do more to describe the returned time-series structure, but it at least names the signal line and histogram.

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?

Parameter schema description coverage is 100%, so the schema already documents all 10 parameters. The description adds no additional semantics for symbol, interval, periods, date filters, or datatype beyond what the schema provides.

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 states a specific verb and resource: fetching MACD technical indicator time series. It also names the returned components (signal line and histogram), but it does not explicitly differentiate this tool from sibling indicator tools such as fetch_ema or fetch_rsi.

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?

There is no guidance on when to use this tool versus alternative indicator tools or when MACD is preferable to SMA/EMA/RSI. Usage is only inferable from the tool name and description.

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