Get time-series observations

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

With no annotations, the description carries the transparency burden. It discloses the 5-series limit and the 10-recent-observations default, but does not mention return format, pagination, error handling, or what 'observations' include. This is adequate but not rich.

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 two sentences, front-loaded with the primary action, and contains no filler or redundant information. Every clause adds meaningful detail.

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 tool with 4 parameters and no output schema, it covers key usage constraints (series limit, default recent count, how to find series). It does not describe the structure of returned observations, which would be useful, but is not severely incomplete.

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 descriptions cover all parameters (100% coverage), so baseline is 3. The description adds value by explaining that when no range is given it defaults to 10 most recent observations, clarifying the relationship between recent and date-range parameters beyond 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?

The description states the specific action 'Fetch observations' for up to 5 Bank of Canada series, with a pointer to search_series for finding names. This clearly distinguishes it from siblings like latest_fx_rates and convert_currency by implying it is the historical time-series 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?

It provides clear context by mentioning search_series for finding names and describing the default behavior when no range is given. It lacks explicit exclusions for alternatives, but the purpose is distinct enough that usage is well implied.

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