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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, and the description does not contradict these. Beyond the annotations, it adds rich behavioral context: the 'greedily filled' priority-order token-budget behavior, the per-section as_of timestamp and citable URL, the omitted field when the budget is exceeded, and the output envelope {sections, used_tokens, omitted}. This gives an agent accurate expectations about side effects and output characteristics.

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?

The description is longer than average but every block earns its place: front-loaded core purpose, contents list, a concrete example, parameter summary, return-shape summary, explicit alternatives, and a required citation. The only minor redundancy is the Params block mirroring the schema, but the overall structure is efficient and well-ordered.

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 an output schema (which already documents return values), safety annotations, two parameters, and a crowded sibling space, the description leaves nothing essential missing: it covers when to use it, when not to use it, alternatives, parameter ranges and defaults, the token-budget filling behavior, the return structure, and even the citation source. An agent has all information needed to invoke it correctly.

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 both parameters have detailed descriptions in the schema, including the max_tokens behavior ('sections are filled in priority order until the budget is spent'). The tool description largely repeats this information, adding an example invocation ('Brief me on ERCOT...') and restating the ISO enum values already in the schema. This is baseline 3: the schema does the heavy lifting, with marginal added value from the example.

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 verb and resource: returns a token-budgeted context pack for a US ISO/RTO, listing concrete contents (grid snapshot, DCPI verdict mix, queue depth, LMP, news). It clearly distinguishes itself from siblings by calling itself 'the narrative briefing pack' and naming alternatives like get_grid_data, get_grid_intelligence, and compare_isos, so an agent can select it without ambiguity.

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?

Explicitly states when to use: 'when an agent needs a WHOLE-grid briefing it can drop straight into its context window.' It also gives a precise do-not-use list: raw single-ISO telemetry (use get_grid_data), per-ISO decision brief (use get_grid_intelligence), multi-ISO scalar comparison (use compare_isos), and non-US grids (use get_grid_scoreboard). This is ideal routing guidance.

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