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 genuine value by naming the underlying data sources (WMATA incidents plus GTFS-realtime feeds) and the unofficial/non-affiliated disclaimer, but says nothing about freshness, latency, coverage limits, or the default behavior with zero filters on a fully optional 4-param tool.

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?

Front-loaded purpose sentence, then a compact per-argument list, then the grounding constraint. Every element is short and scannable. The 'Args:' block is slightly redundant with the schema titles, but it is the only place the accepted value formats live, so it earns its space.

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?

An output schema exists, so return values need not be described, and the remaining burden — accepted argument formats, data provenance, and output-grounding rules — is addressed. The gaps (filter combination semantics, behavior when no arguments are supplied, overlap with the dedicated elevator/escalator tool) are modest but real for a zero-required-parameter tool.

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 0%, so the description carries the full burden and largely does: it defines line as a Metrorail line code with the actual codes (RD, BL, YL, OR, GR, SV) or a bus route number, mode with its three literal values, and agency with example slugs. What it omits is whether filters combine with AND or OR and what an empty filter set returns.

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 states a specific resource and scope: 'Live service disruptions' covering WMATA incidents (Metrorail, Metrobus, elevators) and agencies' GTFS-realtime alerts (detours, closed stops, missed trips). That is concrete enough to distinguish it from most siblings, though the elevator/escalator coverage overlaps with get_elevator_escalator_status and the description never draws that boundary.

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 gives a firm output-grounding rule ('Answer only from this tool's results: never add routes, hours, phone numbers...') and notes it is unofficial, which shapes how results are used. But it offers no when-to-use/when-not guidance against siblings like get_elevator_escalator_status, get_rider_reports or search_transit_info, and does not explain what happens when all optional filters are omitted.

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