Live market watch and top movers

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

Goes well beyond the readOnly/idempotent/openWorld annotations: it discloses the data source (same feed as the site's market watch page), payload size (~3 MB), cache TTL (30 s), a cost warning ("call it sparingly"), and stale-data behavior outside trading hours (shows the last session). It also explains two return fields, `breadth` and `as_of`, that the agent would otherwise misread.

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?

Three dense sentences, zero filler, front-loaded with the what before the when before the cost warning. Every clause is load-bearing: feed identity, size, cache, off-hours behavior, and the `id` handoff all change how an agent calls or reuses the tool.

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 no output schema, the description does enough for a 7-param list tool: it explains the two aggregate fields, notes the 3 MB/cached payload, and explains the `id` handoff. It stops short of describing row shape or pagination behavior beyond `limit`, which leaves some guesswork on large responses.

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 enum/limit/sort descriptions already carry the semantics, so the schema does the heavy lifting and baseline 3 applies. The description adds nothing about the seven parameters — notably it never mentions the `board`, `status`, or `traded_only` knobs that would map to its own example queries.

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 ("Show the live Fara Bourse market watch") and enumerates exactly what each row carries: price, change, volume, best bid/ask. It also scopes the tool (ranked and filtered, ~1,200 symbols) so it is distinguishable from a single-instrument tool at a glance.

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 example intents ("top gainers today", "most traded symbols", "what is trading in the second market") and routes follow-up detail work to ifb_quote and ifb_instrument. However it recommends itself for "which symbols are halted" while a dedicated sibling ifb_halted exists, and it never distinguishes itself from ifb_market_summary — that overlap is left for the agent to guess.

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