dfm_index

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

No annotations provided, so the description carries full burden. It discloses that data may be delayed and is not investment advice. It also lists the returned fields. It does not mention authentication, rate limits, or other potential behaviors, but for a simple index snapshot, the disclosure is adequate.

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?

Extremely concise: two sentences. The first sentence introduces the tool and the second lists outputs and caveats. Every word adds value, no repetition.

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 no parameters and an existing output schema (not shown), the description is complete. It tells the user exactly what the tool does and what to expect. It covers purpose, return fields, and important caveats (delay, not advice).

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?

No parameters exist, so schema coverage is 100%. The description adds value by stating '(no key)' indicating no input is needed, which is helpful beyond the empty schema. Baseline with high coverage is 3, but the extra hint justifies a 4.

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 it returns the latest DFM General Index snapshot with an intraday summary. It specifies the fields returned: index value, change, change percentage, volume, timestamp, and intraday OHLC. This distinguishes it from sibling tools like dfm_stock_quote (for individual stocks) and dfm_list_securities (for listings).

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 clear context: it is for the DFM General Index, not for individual securities. However, it does not explicitly state when to use this vs. sibling tools or include exclusions. The context is sufficient for a knowledgeable user.

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