dfm_list_securities

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

Annotations already declare readOnlyHint, idempotentHint, openWorldHint and destructiveHint=false, so the safety profile is covered. The description adds one genuine behavioral note — "(no key)", meaning no authentication/API key is needed — but says nothing about pagination or the 50-item cap, which the schema happens to carry instead.

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?

One sentence, front-loaded with the verb and resource, with no filler. The trailing parenthetical "(no key)" is compact but slightly cryptic in placement, keeping it just below a perfect score.

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?

With an output schema present and annotations covering safety, the description need only cover scope and filtering, which it does. The remaining gap is sibling disambiguation against dfm_stock_quote/dfm_index, which is not addressed.

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 coverage is 100% and the single `search` parameter is documented in detail (case-insensitive substring on symbol or name, empty → first 50 alphabetical, total count reported). The description only restates "filtered by symbol or name", adding no format or matching semantics beyond the schema, so the baseline 3 applies.

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 ("List DFM-listed securities") plus the filter dimension (symbol or name), which reads clearly against siblings like dfm_stock_quote or dfm_index. It stops short of explicitly distinguishing itself from those siblings, so an agent must infer that this is a bulk enumeration rather than a single-quote lookup.

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 word "optionally" tells the agent the filter is not required, which is minimal usage guidance. It never says when to prefer this over dfm_stock_quote or dfm_index, nor what to do after listing, so the routing decision is left to inference.

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