screener_reference

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

Annotations already declare readOnlyHint, idempotentHint and destructiveHint=false, so the safety profile is fully covered and the description doesn't need to restate it. What the description adds is only content scope, not behavior — it doesn't say whether the reference is static documentation, whether results are cached, or roughly how large a response 'all' produces. With annotations carrying the safety burden, a 3 is appropriate.

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?

Two short sentences: the first states what content is available, the second states when to call it. Zero filler and the trigger condition is placed where an agent will read it.

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 single-optional-parameter reference tool with full annotation coverage, the description covers both content scope and invocation trigger. The only gap is that with no output schema, it never indicates the return shape — docs text vs structured field list — which matters for an agent deciding between topic='fields' and topic='all'.

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% and the schema itself enumerates the topic values (overview, fields, functions, presets, syntax, examples, all), so the description adds nothing about parameter meaning beyond listing the same content categories. Baseline 3 per the schema-coverage rule; notably the description omits 'syntax' and 'overview' from its list, which is a minor inconsistency with 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?

Names a specific resource — reference material (fields, functions, presets, examples) for screen_stocks filters — and implicitly distinguishes itself from the sibling screen_stocks execution tool. It lacks an explicit verb like 'returns' or 'looks up', but an agent can tell this is the documentation companion to filtering rather than a data-returning tool.

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?

Gives concrete trigger conditions: 'when a filter is rejected' or 'you need a field name.' That is an actionable when-to-use rule tied to a failure state of screen_stocks. It stops short of stating when not to call it (e.g., don't preload it before every screen), but the primary guidance is clear.

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