compras_pncp_modalidades

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

Annotations already mark this as readOnly, idempotent, and non-destructive, but the description adds genuinely useful behavioral context: it is a local tool that does not call upstream, its source is the official PNCP table, and there is a critical ecosystem-wide distinction between two modality-code tables. This helps an agent understand edge cases around data equivalence without needing external knowledge.

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 compact and well-structured: the core purpose is stated first, followed by the local/source facts, then the crucial disambiguation warning. Every sentence adds value, and the warning about the two tables is essential, not filler.

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 zero-parameter reference tool with an output schema present, the description provides all necessary context: what the data is, where it comes from, how it relates to other tools, and how to handle the Dados Abertos enum discrepancy. Nothing important is missing for an agent to use the tool 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?

The tool has zero parameters, so the empty input schema carries no burden. The description appropriately focuses on what the returned codes mean rather than parameter details, which is the relevant semantic context for a parameterless reference tool.

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 clearly identifies the tool as a local cheat sheet for PNCP contracting modality codes, with a specific scope and source (official PNCP table from Lei 14.133). It distinguishes itself from related tools by explicitly warning that its `codigo` is the PNCP enumeration used across all `compras_pncp_*` tools, whereas Dados Abertos/SIASG uses a different enumeration.

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?

The description gives explicit guidance on when this tool's codes apply and names the alternative endpoint (`compras_contratacoes_14133_listar`) for the different Dados Abertos/SIASG enumeration. It also explains the `equivalente_dados_abertos` field and its `None` value, which helps an agent choose correctly between the two encodings.

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