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

Annotations already declare readOnlyHint=true and destructiveHint=false, and the description adds useful behavioral context: no 52-week-range or volume filtering because those are not tracked for indices, and the output is a CSV with one row per matching index. This goes beyond the structured annotations without contradicting them.

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?

Every sentence earns its place: the first defines scope and criteria, the second states exclusions, the third gives use-case and sibling distinction, and the fourth states return format. It is concise, front-loaded, and free of fluff.

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 a complex 12-parameter tool with no output schema, the description covers the essential context: what is screened, what filters exist and which do not, how it differs from related index tools, and what the return format is. The schema handles parameter-level details, so nothing critical is missing for correct invocation.

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 100%, so the baseline is 3. The description adds meaning beyond the schema by framing the filter parameters as the same pre-computed technical criteria used by screen_stocks and explicitly noting what filters are absent. This helps the agent understand the parameter set's collective purpose, even though individual parameters are already well-described in the 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?

The description names a specific verb ('Screen'), a specific resource ('CSE sector/headline indices'), and the core criteria (moving-average position, relative-strength rating). It also distinguishes itself from get_indices/get_index_data by contrasting screening with single-day performance, so an agent can tell exactly what this tool does.

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?

It explicitly states when to use the tool ('Use this to find which sectors are in a sustained uptrend/downtrend') and explicitly contrasts it with get_indices/get_index_data, which show a single day's performance. The reference to screen_stocks as the shared methodology further clarifies the filtering family.

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